Develop Bugs

32gb class2 or 16gb class6+ SDCARD

I'm trying to decide if i should go for space, or speed.
For those of you that bought 32gb cards, are they class2? and if so do apps and such run off it fine, playing movies?
Class 6 is much more fast, and a class6 16gb card is still half the price as a class 2 32gb card.
Just looking for guidance here, do we need more then class2 for our phones.
Plan on putting movies and apps and stuff on the card.

I have a 16GB class 2 card in my Cappy, and I can play 720p video off it without a single stutter, and I never did install the lagfix, so class 2 SHOULD be fast enough, depending on what you want to do with it.
But right now, the cost of the 32GB cards is, I think, prohibitive. It costs > 3x what I can get a 16GB card for, and thus far, I have not filled my card yet.

I would go with a faster speed for the bigger size card, class 2 would be too slow if you are read/write onto it constantly; For the best bang of your buck, the Polaroid 16GB microSD (made in Japan by PNY) from Frys is going for under $20 (after rebate); Even though it is labeled as a Class 2 card, but under most SD benchmark app, it is detected as a Class 4 card (4.5 MB/s Write/15 MB/s Read under the 300MB file R/W test in SD Card Speed Test)

I would rather take a 2GB class 6 over a 32gb class 2. Class 2 is so unbelievably slow its unbearable. I use my phone as a usb drive very often. In my previous phone I had an 8gb class 2. It was so slow I thought the card was broken. So I RMAed it and the new one was the same. I realized that it just takes like 8min/gb to transfer to it. (and no its not faster in this phone)
Class 4 is standard, anything less is a waste of silicon and plastic.
Class 6 is about as fast as your average-quick USB thumb drive.
Yes class 2 is fast enough to run programs and play back video, but you'll spend a lifetime transferring those things.
Not worth it IMO. Get an 8gb class6 if cost is an issue. Also, don't go with any crappy random manufacturers. I find that a class 6 from 'craptasticMEM' is nowhere near the speeds it should be, and in fact usually slower than a clas 4 I have from kingston.

The class rating has nothing to do with playback speed, only write speed. Copying files is faster, but how often are you loading up your SD card from your computer?
I am using class 2 and it is recording video just fine. I am not sure why above poster claims "class 4 is standard" - that would imply that class 2 is sub-standard. It is not, it just has slower write speed.
Keep in mind that if you lay out the big bucks for a class 6 32GB card today, it will half the price in a few months.
Now in my HD Camcorder it requires Class 6 to record 1080P - our phones have no such requirement, so anything above class 2 will help in initial data transfer from PC - after that you may never, ever see any benefit.

alphadog00 said:
... I am not sure why above poster claims "class 4 is standard" - that would imply that class 2 is sub-standard. It is not, it just has slower write speed.
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Yes, sorry you're correct. Class 4 is standard in my gauge of memory cards/usb drives. All the classes "should" perform fine. The higher classes are obviously faster (with significant brand to brand variation). I find that they are faster at everything though. Not just write, but read as well. A class 6 card is as smooth as the internal memory in the captivate. A class 2 card is abysmal at everything (in my experience). I say class 4 is standard because class 2 is really bad...

eatkabab said:
Yes, sorry you're correct. Class 4 is standard in my gauge of memory cards/usb drives. All the classes "should" perform fine. The higher classes are obviously faster (with significant brand to brand variation). I find that they are faster at everything though. Not just write, but read as well. A class 6 card is as smooth as the internal memory in the captivate. A class 2 card is abysmal at everything (in my experience). I say class 4 is standard because class 2 is really bad...
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Click to collapse
It could be my blindness - not physically, but the ignorance of not having a class 4 or 6 to compare to my class 2. My class 2 works fine for me, but if the class 6 stuff gets cheap I will head on over to it.

alphadog00 said:
It could be my blindness - not physically, but the ignorance of not having a class 4 or 6 to compare to my class 2. My class 2 works fine for me, but if the class 6 stuff gets cheap I will head on over to it.
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Click to collapse
My 32GB Class 2 reads/writes as smoothly as the internal card on the captivate as well.

locsplitter said:
My 32GB Class 2 reads/writes as smoothly as the internal card on the captivate as well.
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Click to collapse
lol no
internal is like class 10 i believe

locsplitter said:
My 32GB Class 2 reads/writes as smoothly as the internal card on the captivate as well.
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Click to collapse
its not healthy to lie

you guys are missing the fact that the class ratings are a MINIMUM rating. a lot of brands will perform MUCH faster than what they have printed on them. just saying something is class X is pretty much pointless. it's just a guideline that is being loosely followed. benchmark and move on

If your running apps off of your card than believe me there is noticable difference between a class 2 and a class 6, and yes dont go for a no name.
Sent from my SGH-T959 using XDA App

demize! said:
If your running apps off of your card than believe me there is noticable difference between a class 2 and a class 6, and yes dont go for a no name.
Sent from my SGH-T959 using XDA App
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I don't believe you. It 100% fully depends on the card. Some class 2's are faster than class 6's. Ratings are lies.... benchmark ftw!

True that. Ive found significant differences by brand. However, there is definitely a noticeable difference between a class 2 and a class 6 card.
What you get depends on personal requirements more than anything else. Faster or more storage?

[Q] Why class 6 SD card?

Hi all,
I've read in a few places that if you want to run apps from your SD card that you should have a class 6 SD card. Can anyone explain why this is? I've currently got the one that came with the phone, which is class 2. Just want to understand why I need it before splashing out the cash
Thanks

It's all about speed. Class 6 is faster than Class 4 is faster than Class 2. If you are happy with the performance with your Class 2 card, no need to splash out the cash.

yeah its just about speed, the higher the class the faster the r/w speed, you dont really need a class 6 these days tho, maybe in the old days of the g1/hero but not now

There's quite a bit of discussion on this and I'm honestly quite confused over this as well.
The higher classes just means faster write speeds but same read speeds. Certainly, this shouldn't affect the performance of apps that are installed on the card; unless the card is being used for swap memory.
Anyway, I've heard some users with 32GB microSD card (only available in class 2) using app2sd with no ill-effects. I've recently purchased one myself and will be swapping it out later tonight.

newbie on Android here.....may I ask....Im currently using a 16Gb mem card....If I change it to a 32Gb, what are the files that I need to copy to the new card, so that the apps/games currently installed will still run? I noticed there are so many folders inside my memory card now.....which one should I transfer to my new card? Or should I need to re-install the apps?
thanks..

dinoalbert said:
newbie on Android here.....may I ask....Im currently using a 16Gb mem card....If I change it to a 32Gb, what are the files that I need to copy to the new card, so that the apps/games currently installed will still run? I noticed there are so many folders inside my memory card now.....which one should I transfer to my new card? Or should I need to re-install the apps?
thanks..
Click to expand...
Click to collapse
are you using apps2sd? or just running a stock like rom?

9 out of 10 users on this website would not be able to tell the difference in speed by running apps on a class 4 or class 6 cards.

AndroHero said:
are you using apps2sd? or just running a stock like rom?
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Click to collapse
I am using an OTA Froyo but already rooted....

Before the usual flamers get to write on this topic to say high-class cards are useless, it really comes down I think to the time you have available to wait for USB transfers. On a class 2 it takes AGES. I bought a class10 16gb and it's an absolute life changer (i do have a lot of public transport so I make heavy use of my phone as a video player)

phentex said:
Before the usual flamers get to write on this topic to say high-class cards are useless, it really comes down I think to the time you have available to wait for USB transfers. On a class 2 it takes AGES. I bought a class10 16gb and it's an absolute life changer (i do have a lot of public transport so I make heavy use of my phone as a video player)
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Another reason to have a class 4 or faster card in the phone is to have reliable 720p 25fps video recording. On my Class 2 with a2sd+ recording stutters.

thanks for the responses. from what i read previously, it talked about class 6 cards being less likely to be unmounted and causing problems to running applications. does this mean anything to anyone?!

Kashban said:
Another reason to have a class 4 or faster card in the phone is to have reliable 720p 25fps video recording. On my Class 2 with a2sd+ recording stutters.
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Click to collapse
This is the reason when I eventually get the money I'll be getting a 16GB class 4 or 6 card. At the moment 720p is fairly pointless to me since I can't get smooth recordings with my SD card.

Have no issues with my 16Gb Class-2 sdcard. R/W speed enough to handle 720p recording and rockplayer playing avis perfectly.
Sent from my HTC Desire using XDA App

iLHaNroID said:
Have no issues with my 16Gb Class-2 sdcard. R/W speed enough to handle 720p recording and rockplayer playing avis perfectly.
Sent from my HTC Desire using XDA App
Click to expand...
Click to collapse
Are you running A2SD or a2sd+ on your phone? If not, that may be the reason.
The more apps and widgets and stuff is moved to the sd, the more r/w-access happens to the card, which has serious impact on video recording. I really wish the internal memory of the Desire wasn't so small. What the heck did HTC think by putting only 560 MByte internal storage into their android flagship? The SGS has 5 GiBytes!

jstegeman said:
It's all about speed. Class 6 is faster than Class 4 is faster than Class 2. If you are happy with the performance with your Class 2 card, no need to splash out the cash.
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Click to collapse
Incorrect!
The class of the card doesn't tell you the speed of a card - it tells you the *minimum* sustained write speed on a card which is completely unfragmented
A good quality class 2 card can and often will be faster than a poor quality class 6 card.
The two Sandisk Class 2 card I use both write at around 7.5mb/s, which is faster than the class 6 minimums.
Regards,
Dave

foxmeister said:
Incorrect!
The class of the card doesn't tell you the speed of a card - it tells you the *minimum* sustained write speed on a card which is completely unfragmented
A good quality class 2 card can and often will be faster than a poor quality class 6 card.
The two Sandisk Class 2 card I use both write at around 7.5mb/s, which is faster than the class 6 minimums.
Regards,
Dave
Click to expand...
Click to collapse
That's interesting info! Would explain why I have far fewer problems than most people report with 720p recording onto my class2 card.
So the real answer is: Benchmark your write speed before making any big purchasing decisions on SD cards.

Kashban said:
Another reason to have a class 4 or faster card in the phone is to have reliable 720p 25fps video recording. On my Class 2 with a2sd+ recording stutters.
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Click to collapse
so a class 4 good enough for 720p? i have a class 2 right now and the recording is just horrible.. i thought that my phone was broken and have changed many custom roms

Bought a C6 16gb to replace C2 4Gb - definitely faster as USB drive - both Sandisk

What speed and/or Class card do you use for your memory card?

Hey
Im sorta "hell bent" on getting a 32GB microSD Class 10 card ( http://forum.xda-developers.com/showthread.php?t=1031312 ) but they are very limited to find. I want a Class 10 because of data transfer and the snapping of pictures/video taking is alot quicker.
I just want to know what class did you get, for what purpose, and what do you use your mobile device most (taking pictures, internet, calling, etc).
Just so everyone knows (just in case):
The Speed Class Rating is the official unit of speed measurement for SD Cards, defined by the SD Association. The Class number represents a multiple of 8 Mbits/s (1 MB/s), and meets the least sustained write speeds for a card in a fragmented state.
Click to expand...
Click to collapse

Hey,
I was really keen on getting a class 10 32Gb too, but they are very expensive. In then end I opted for a 16Gb class 10 as Play.com had them on offer a month or so ago. I got a sandisk one. Just had a look for a link, but I don't think they have them now.
Guess you could get it anywhere though. I paid £15 including delivery.
I've done a couple of measurements and it's definitely performing at class 10 speeds. I have an HD2 running an Android Gingerbread SD build and the speed has been more than adequate.
My use is mostly internet, texts and calls. I have done some video/photo stuff since getting the card and it's definitely fast enough.
I used to have a class 6 PNY 8Gb one in there and it's a hell of an improvement, especially now I'm on an SD build. The only thing I would say is android takes a fair while to do it's 'preparing SD card' business when I turn the phone on, but no other issues to report. the new card seems to have helped with the hang issues on installing market apps too, which is nice.
Also - did a defrag on it with Mydefrag (beautiful tool!), which seems to have helped too.
Hope that helps!

I still use my stock 8GB card I got with my phone. My main use is pictures and apps. Its a class 2.
Sent from my HTC Inspire 4G
XDA Developers Premium App

I'm currently using 2 32GB Sandisk cards... one is marked class 2, one is marked class 4, but both their average write speeds are pretty similar. They could accurately be marked as class 6.
But really, the class is not important to me. When it comes to choosing a card to use in my phone, I look for cards with quick access times and fast random read and write speeds. Class ratings are really only important when the cards are going to be used in a digital camera or be used as a flash storage drive where you will be transferring large files back and forth.
When it comes to cell phones, a card that can quickly access files and can read/write to many different parts of the card quickly is much more important than a card that can write sequentially fast. You may be able to take large pictures with the camera more quickly with a higher class card, but many cards sacrifice their random access speeds to get that high sequential write speed. This can cause lags and performance loss when running apps or system files off the higher class cards.
The best cards to generally use in cell phones is a class 2 or 4. Many class 6 may perform well, too. There may even be class 10 cards that don't sacrifice that random access speeds. Quality and brand are generally much more important than class to get good access speeds and random read/write speeds.
I really think there needs to be a new rating system for access speeds and random speeds. In general, the lower class cards have better random access speeds, but that's not always the case. There are plenty of class 2 and 4 cards that have terrible random access times, and many class 6 and even 10 that still have great random access. Unfortunately, there's no way to know how a card rates in these areas until you actually test it.
I've always had good results from Sandisk cards... and terrible results from Kingston.
Hopefully, since WP7 requires cards used with it to have good random access speeds, we might start seeing some lines of microSD cards that rate these speeds.
But for now, if you're using the card with wp7, or running android off the card, or running apps or other system files off the card, you will generally have better results with high-quality lower-class cards. I have only been using Class 2 and 4 Sandisk recently. Hopefully a new class and rating system is created for using these cards with smartphones. We are using them more and more for the purpose of internal phone memory... especially windows phone 7, and even with android you see more people making partitions on their cards to use as internal memory to run app and system files. We need a better rating system for cards, cause the current class rating is pretty much meaningless for smartphone purposes.

homescrub said:
I still use my stock 8GB card I got with my phone. My main use is pictures and apps. Its a class 2.
Sent from my HTC Inspire 4G
XDA Developers Premium App
Click to expand...
Click to collapse
Thanks but vote
Seiphr said:
Also - did a defrag on it with Mydefrag (beautiful tool!), which seems to have helped too.
Click to expand...
Click to collapse
Defraging a flash based storage device does nothing and actually makes its lifetime smaller.
zarathustrax said:
I'm currently using 2 32GB Sandisk cards... one is marked class 2, one is marked class 4, but both their average write speeds are pretty similar. They could accurately be marked as class 6.
But really, the class is not important to me. When it comes to choosing a card to use in my phone, I look for cards with quick access times and fast random read and write speeds. Class ratings are really only important when the cards are going to be used in a digital camera or be used as a flash storage drive where you will be transferring large files back and forth.
When it comes to cell phones, a card that can quickly access files and can read/write to many different parts of the card quickly is much more important than a card that can write sequentially fast. You may be able to take large pictures with the camera more quickly with a higher class card, but many cards sacrifice their random access speeds to get that high sequential write speed. This can cause lags and performance loss when running apps or system files off the higher class cards.
The best cards to generally use in cell phones is a class 2 or 4. Many class 6 may perform well, too. There may even be class 10 cards that don't sacrifice that random access speeds. Quality and brand are generally much more important than class to get good access speeds and random read/write speeds.
I really think there needs to be a new rating system for access speeds and random speeds. In general, the lower class cards have better random access speeds, but that's not always the case. There are plenty of class 2 and 4 cards that have terrible random access times, and many class 6 and even 10 that still have great random access. Unfortunately, there's no way to know how a card rates in these areas until you actually test it.
I've always had good results from Sandisk cards... and terrible results from Kingston.
Hopefully, since WP7 requires cards used with it to have good random access speeds, we might start seeing some lines of microSD cards that rate these speeds.
But for now, if you're using the card with wp7, or running android off the card, or running apps or other system files off the card, you will generally have better results with high-quality lower-class cards. I have only been using Class 2 and 4 Sandisk recently. Hopefully a new class and rating system is created for using these cards with smartphones. We are using them more and more for the purpose of internal phone memory... especially windows phone 7, and even with android you see more people making partitions on their cards to use as internal memory to run app and system files. We need a better rating system for cards, cause the current class rating is pretty much meaningless for smartphone purposes.
Click to expand...
Click to collapse
Great post as in the other thread I may have to go with a Class 4 (as there are even less Class 6) card as it will also lower the price in my budget. Cant have everything...

I got a good deal on a Samsung 16 gb class 2, figured I'd go for it because I don't really use my phone for too much HD recording . However, it consistently benchmarks at class 6 speeds.
Yes, I did vote

32gb sandisk class 4

No clue, is there a program which can be used to check it in a SGS?

johan81 said:
No clue, is there a program which can be used to check it in a SGS?
Click to expand...
Click to collapse
h2testw
Thanks

Thanks for all the votes
It seems since Im on a budget, Im going to have to go with a Class 4 even though it hurts as I (thought) a Class 10 was needed. I just hope I dont notice it when taking pictures.
SanDisk without a doubt right?

riahc3 said:
SanDisk without a doubt right?
Click to expand...
Click to collapse
Im tempted to make a thread about this as well
I just like to make sure what I buy before I do it. Makes me more sure about what Im buying.
Thanks to everyone who has helped me in these 2 (well problably soon 3) threads. I appreciate it

riahc3 said:
Im tempted to make a thread about this as well
I just like to make sure what I buy before I do it. Makes me more sure about what Im buying.
Thanks to everyone who has helped me in these 2 (well problably soon 3) threads. I appreciate it
Click to expand...
Click to collapse
Definitely Sandisk....if getting 32GB, look for model # ending in B35A or B35N. I think that's the one I got. I'll double check tonight and let you know. It was listed as class 2 when I ordered it, but it was marked class 4 when I got it, and it had sequential write speeds equal to class 6 (6MB/Sec). I also have a 32GB with model # ending in A11M... this one was mark class 2, but I think newer ones are also marked class 4. Not sure if the newer ones marked class 4 have better performance than the ones marked class 2, but mine which is marked class 2 could also easily be marked class 6 and be as fast in sequential write speeds as most class 6 of other brands... but the class 2 A11M is not quite as fast as the class 4 B36A that I have in both sequential write/read and random read/write & access times. But like I said, the newer A11Ms marked as class 4 may have better performance than the ones marked class 2, and the performance difference between my 2 32GB Sandisks is not very big.... both are VERY good cards in overall performance.
I got both my cards from provantage, I believe.

zarathustrax said:
The best cards to generally use in cell phones is a class 2 or 4. Many class 6 may perform well, too. There may even be class 10 cards that don't sacrifice that random access speeds. Quality and brand are generally much more important than class to get good access speeds and random read/write speeds.
Click to expand...
Click to collapse
Hey zarathustrax, I'm maintaining a microSD benchmark results thread and we have quite a few results now, and it backs up everything you are saying. The 32GB Class2 Sandisk (when it was available) owns everything on random writes. Followed by the 32 Class4 Sandisk.
By comparison, a 32GB Class10 Lexar is benching 350 times slower for random writes than the Sandisk. And yet only offers a doubling of sequential write speed.
Additionally, I maintain an in-phone microSD benchmark thread too. But the results are pretty much cached out by whatever ROM you are running on your phone. So slow cards become much faster, and fast cards become much slower. In the end we found that all cards were performing at around the same speeds. Its only when you changed ROMs would you see a change in in-phone card speed.
Out of phone benchmark link...
http://forums.whirlpool.net.au/forum-replies.cfm?t=1582172
In-phone benchmark link...
http://forums.whirlpool.net.au/forum-replies.cfm?t=1468705

Thanks. Im going to read your links now and see if there are model numbers and get some cards (I should have already bought the card before yesterday)
Thanks again stumo5

Damn, no model numbers

Stores that are near me and deliver to me only offer Kingston lol...

Holy ****!
I have found one that has a Sandisk; The only problem is that on the webpage it says that it is a SDSDQM-032G-B35 but the picture shows a 2 written on the card, meaning Class 2. I pretty much refuse going from a Class 10 to a Class 2 and besides the price is 95....
Im going to call and get the model number anyhow....

Kingston 60 bucks
Sandisk 95 bucks
Man how they like to **** consumers in the ass Anyways, he said that what was shown to him was divided by categories and he couldnt tell me the exact model number as it just showed him prices and who supplied it but I rather pay on eBay a Lexar Class 10 at 96 rather than a Sandisk Class 2/4 at 95.
More comparisons: A Sandisk Class 2 32GB at 89 bucks on eBay.
I mean I really have to juggle and ask my self: Is it really worth it? Being on a slight budget, Im not sure.
stumo5 - Has anyone done tests in your microsd exam on TopRAM? I might get them at the end as the prices are just rapist ( ). zarathustrax, the price doesnt justify to me at the end, unless I will notice it.
My main dilema was how pictures were going to be taken as I imagine there will be a lag in picture when I press it and when it is actually taken. Also file transfers and installing/running applications from the SD card. Your explanation was great zarathustrax but Im not sure if its going to be worth the price.
My first smartphone (Nokia E70) I went with Kingston but it surprises me in a way that people talk so bad about Kingston in the flash memory card area.

And I now see on eBay a Sandisk 32GB Class 4 at about 75....More or less.

I'm currently using the 8gb one that came with my Desire Z although I have a class 6 8Gb somewhere that I bought but I haven't felt the need to swap yet for some reason I can't tell a difference

What Type Of MicroSDHC Class, Should I Buy For Arc?

Hey Ppl...
What Type Of MicroSDHC Class, Should I Buy For Arc?
Class 4, 6 or 10?
Right now i´ve Class 2

Its better to get the highest which is class 10 if u can afford..

The Classes guarantess a lowest speed while newely formated
class 2 is 2MB/s
class 6 is 6MB/s
class 10 is 10MB/s
and so on
but with luck a class 2 card can outpreform a class 6 card but you never know untill you have bought it.
the use of a higher class is more important how often you transfer big amout of files/data from and to your phone (this is when you will notice a slow card)
everyday use the class 2 card that is shipped with the phone works perfect

I'm going for a 16GB Kingston Class 10 for mine, might go 32GB but that'll depend on how much I get for my X10 on ebay.

XperienceD said:
I'm going for a 16GB Kingston Class 10 for mine, might go 32GB but that'll depend on how much I get for my X10 on ebay.
Click to expand...
Click to collapse
Put my X10 on ebay yesterday!
How much you asking for it?
For no OT, I bought a 32 GB Lexar class 10 MicroSDHC

LususNaturae said:
Put my X10 on ebay yesterday!
How much you asking for it?
Click to expand...
Click to collapse
Not sure yet, it's a bit weared so not expecting a great deal.

Here's the thing: the class of an SD card only defines how fast you can *write* to it. The read speeds of all cards tend to be the same regardless of class.
What a faster class of SD card will get you:
* faster copying of files from PC to SD, e.g. music, video
What it won't get you:
* a faster running phone (i.e. no 'snappier' performance)
* apps loading faster
* faster copying of files from SD to PC
* music/video playback improvements
* faster installation of apps - these are stored in internal memory, and even for builtin apps2sd the limiting factor tends to be the download speed
What it might get you:
* faster stills camera operation (havent checked for the arc, there may be bottlenecks elsewhere in the system, e.g. cpu)
* i thought it might solve the video capture glitching, but apparently the new firmware has fixed this regardless of SD card class.
* some apps which write a lot of data to SD card may run faster (note however that for most apps data is stored in internal storage)
Nothing inherently wrong with getting a faster card, just dont delude youself you'll see much of a difference in day-to-day operation.
Oh, i forgot, EXCEPT one other thing: If youre using 'full' apps2sd on a rooted phone (i.e. with an ext2 partition moving all apps+data+dalvik cache onto it) it will definitely help to have a faster class of SD card. Dunno if anyone really still does that these days...

I've always found going bigger and faster to be best, but valid points made.

daveybaby said:
Here's the thing: the class of an SD card only defines how fast you can *write* to it.
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Click to collapse
That's incorrect - the class rating is a guarantee of both read and write speeds.
daveybaby said:
The read speeds of all cards tend to be the same regardless of class.
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Click to collapse
You can't guarantee that any more than you can guarantee that a Class 2 card will write at speeds higher than 2MB/s.
The only way to be sure of getting a card that will read at a certain speed is to buy the appropriate class.

Step666 said:
That's incorrect - the class rating is a guarantee of both read and write speeds.
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Click to collapse
That's a nice opinion, but unfortunately it's just wrong.
Have a look at this. Notice they dont mention read speeds anywhere, that's because theyre already so fast regardless of class that it's irrelevant.
When you buy a class 10 SD card, youre spending your money on faster writes.
The read speeds of all cards tend to be the same regardless of class.
Click to expand...
Click to collapse
The limiting factor in read speeds is the interface, not the memory technology. I believe SDXC may have faster interface specs than SDHC (which in turn has faster specs than plain SD), but this is nothing to do with class, and make no difference if youre plugging them all into an SDHC device anyway.

Try reading that page again, it doesn't say that the class certification is a measure of writing speed, it says it's the bus-interface speed - it merely mentions write speeds as examples of why you would need higher speeds in real life.
The read speeds that the cards are actually capable of may well be higher but in practice the write speeds are almost always higher too - but there's no guarantee they are.

Step666 said:
Try reading that page again, it doesn't say that the class certification is a measure of writing speed, it says it's the bus-interface speed - it merely mentions write speeds as examples of why you would need higher speeds in real life.
Click to expand...
Click to collapse
So it's just a coincidence that nowhere does anyone mention read speeds, only write speeds and recording, when talking about flash memory. Because nobody's interested in read speeds, right?
Look, the read speeds of flash memory devices are stupidly high compared to write speeds (and always have been), and are limited by the interface, the write speeds are limited by the technology of the memory itself (which is the bit all of the manufacturers have spent millions (probably billions actually) improving over the last 10 years.
I hate quoting wikipedia articles but:
The Speed Class Rating is the official unit of speed measurement for SD Cards, defined by the SD Association. The Class number represents a multiple of 8 Mbits/s (1 MB/s), and meets the least sustained write speeds for a card in a fragmented state.[17]
These are the ratings of all currently available cards:[14][24]
Class 2, 2 MB/s
Class 4, 4 MB/s
Class 6, 6 MB/s
Class 10, 10 MB/s
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I can see this going round in circles. From what I've read, basically, if you put a class 10 card in a phone that has been running a class 2 card then you're not going to see the difference like you would putting 4GB of memory in a PC that has been running on 512MB, but having a higher class of card will improve some areas behind the scenes so to speak.
If I didn't have an X10 to sell then chances are I'd stick with my class 6 Samsung but as I'll have the money to go class 10 I am doing.

daveybaby said:
Look, the read speeds of flash memory devices are stupidly high compared to write speeds...
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And?
Real-world write speeds on cards are generally higher than their class rating would suggest but you are only guaranteed the speed corresponding to the class the card is.
Exactly the same applies to read speeds, they will most likely be much higher in real life but you are only guaranteed the speed that corresponds to the rated class of the card.
The class of a card guarantees minimum read and write speeds but both will likely be noticeably higher in real life.

Class has nothing to do with read speed period. Manufacturers only guarantees the write speed based on classifications because read speed will only be the same for all class of cards. Try the "Sd Tools" app if you don't believe me.
Therefore, unless you are using the defunct "app2sd+ data, dalvik", there should not be any discerning difference except for its higher price.
Sent from my LT15i using XDA App

Step666 said:
And?
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And the read speed limit is defined by the interface implementation not by the class of the card. When i say flash read speeds (i.e. reading data from the cell) are fast, i mean theyre to all intents and purposes instantaneous, they always have been - they havent gotten any faster in the last 20 years - it's inherent in the technology. The thing that takes all the time is shuffling the bits of data across the serial interface.
It's entirely possible for a class 2 card by one maufacturer to have faster read speeds than a class 10 card by another manufacturer. It's entirely possible for the same card to have different read speeds in different devices due to the interaction of the interface implementations (subtle timing differences). Write speeds arent affected by this as much because the bottleneck is the large amount of time it takes to erase a cell and rewrite it.
Note that if you have a really old class 2 card, it's probably going to have much slower read speeds than a brand new class 10 card. This is not inherently due to the class of the card, it has everything to do with the fact that manufacturers only implemented faster interfaces to handle class 10 cards once the technology to *write* at this speed became available. Due to economies of scale they implement these faster interfaces across the board. New class 2 cards will be able to read as fast as new class 10 cards.
That's all i'm going to say on this matter, if you dont believe me you dont believe me, i'll agree to disagree.

daveybaby said:
That's all i'm going to say on this matter, if you dont believe me you dont believe me, i'll agree to disagree.
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I'm afraid I don't, we'll have to disagree.

The sdhc that came in the box has a class 2 rating in it but using sd tools, it writes at 6mb/sec average, bursting at 9mb/sec. Read speed is the same as my older 8Gb class 6 at 19-20mb/sec.

Step666 said:
I'm afraid I don't, we'll have to disagree.
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Cool

I have Sandisk Micro HDSD 16GB Class 2 but in SD Tools Write Speed: 10.1Mb/s, Read Speed: 27.5Mb/s

So I bought a UHS-3 SD Card for my G3. Overkill?

Hi
I bought a SanDisk Extreme UHS-3 SD Card out of impulse today.
I'm unsure if the G3 has enough bandwidth to deal with it.
Has anyone bought a UHS-3 SD Card and is using on his G3?
Tapatalked thru my LG G3

Bump
Nobody tried? Couldn't find any info either
Tapatalked thru my LG G3

I am using a 64gb Sandisk extreme UHS-I U3 (UHS Level 3) card. Seems to work fine. I don't understand what issue you were logically expecting to experience.

gandalf_grey91 said:
I am using a 64gb Sandisk extreme UHS-I U3 (UHS Level 3) card. Seems to work fine. I don't understand what issue you were logically expecting to experience.
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Improved speeds etc. I thought about using MultiROM on it.. Could you please run A1 SD bench and post the results?
I'm getting pretty much the same card as you

GTMoraes said:
Improved speeds etc. I thought about using MultiROM on it.. Could you please run A1 SD bench and post the results?
I'm getting pretty much the same card as you
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Read 67.05MB/s Write 31.64MB/s

gandalf_grey91 said:
Read 67.05MB/s Write 31.64MB/s
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Write speed looks very good, but read is disappointing...
thanks! But it seems that the G3 is limited to UHS-I =/

I am getting 38.44 and 20.03 only for samsung evo uhs 1 I guess your result is pretty good

Zenroid said:
I am getting 38.44 and 20.03 only for samsung evo uhs 1 I guess your result is pretty good
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I'm using a Samsung Class 10 SD Card. Terrible 44.34MB/s read and 17.38MB/s write, default benchmark
Using the Precise Benchmark, I'm getting 59.7MB/s read and 19.22MB/s write. It's too bad.
In comparison, I'm getting 183.92MB/s read and 38.7MB/s write on the internal memory (precise benchmark, with reboot)
I expected somewhere near the internal memory read speeds with the Sandisk extreme, but at least there's the decent write speed.
I wanted to run some ROMs on the memory card, but with those read speeds, it doesn't seem feasible.
Or perhaps the G3 internal memory is just absurdly fast. I'll try with some other devices around my home
---
Funny. The Galaxy S4 Mini here has slower internal memory than my Class 10 SD Card. But still, if I install Android on my SD Card, it'll be as slow as taking 10~20 seconds to open a simple app.
I don't get it

gandalf_grey91 said:
Read 67.05MB/s Write 31.64MB/s
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Just received my UHS-3 card.
Pretty disappointed by the read speeds.
I was getting ~65MB/s read and ~14MB/s write.
The SanDisk Extreme is giving me ~48MB/s read and ~30MB/s write.
Massive improvement in write, but messed up in read.... I don't know what's wrong

GTMoraes said:
Just received my UHS-3 card.
Pretty disappointed by the read speeds.
I was getting ~65MB/s read and ~14MB/s write.
The SanDisk Extreme is giving me ~48MB/s read and ~30MB/s write.
Massive improvement in write, but messed up in read.... I don't know what's wrong
Click to expand...
Click to collapse
Being the inventor of trans flash memory, Sandisk seems to feel the need to provide a distinct USP, over and above the competition, for it trans flash memory products. Unfortunately this usually means they are surfing very close to edge of their fabrication technology. I base this on my observation of the ever-changing product code attached to Sandisk 128GB micro sd cards, which has changed 3 times in the last 10-12 weeks.
Put simply, like CPUs, I believe Sandisk are speed testing and grading their trans flash products, the extreme range is exactly the same as the ultra range, only labeled and marketed differently. Because there is no distinct technological advantage, there is likely to be a more pronounced range in both read and write speeds. So, while a tested write speed of, for example, 30MB/s may mean an individual micro sd card can be labeled as "extreme" by Sandisk, doesn't mean its read speed will be consistent with every other micro sd card labeled as "extreme".
Oh, and remember, only 4KB random write speed is the true write speed test for memory cards. This is the specification that makes the real difference if you need to boot an OS from the card.

gandalf_grey91 said:
Being the inventor of trans flash memory, Sandisk seems to feel the need to provide a distinct USP, over and above the competition, for it trans flash memory products. Unfortunately this usually means they are surfing very close to edge of their fabrication technology. I base this on my observation of the ever-changing product code attached to Sandisk 128GB micro sd cards, which has changed 3 times in the last 10-12 weeks.
Put simply, like CPUs, I believe Sandisk are speed testing and grading their trans flash products, the extreme range is exactly the same as the ultra range, only labeled and marketed differently. Because there is no distinct technological advantage, there is likely to be a more pronounced range in both read and write speeds. So, while a tested write speed of, for example, 30MB/s may mean an individual micro sd card can be labeled as "extreme" by Sandisk, doesn't mean its read speed will be consistent with every other micro sd card labeled as "extreme".
Oh, and remember, only 4KB random write speed is the true write speed test for memory cards. This is the specification that makes the real difference if you need to boot an OS from the card.
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That was very informative. Yes, it seems that Sandisk is pushing any 30MB/s write card as Extreme, and if it complies with a minimum read (very minimum it seems), it's off to go.
I'm unsure whether should I return this card (need to pay shipping costs) or keep it as it is
Many thanks for this answer! I'll check for random 4kb write to see which one fares better
Tapatalked thru my CM12 G3!

GTMoraes said:
I'm unsure whether should I return this card (need to pay shipping costs) or keep it as it is
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Two quotes from the Sandisk legal statement about Extreme 64GB micro sd card:
2) Card only. Up to 80 MB/s read; up to 50 MB/s write. Based on internal testing; performance may be lower depending upon host device.
(4) UHS Speed Class 3 designates a performance option designed to support real time video recording in U3-enabled host devices.
---------- Post added at 11:41 PM ---------- Previous post was at 11:26 PM ----------
GTMoraes said:
I'm unsure whether should I return this card (need to pay shipping costs) or keep it as it is
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Sorry, previous numbers were for 64GB Extreme Plus micro sd cards (Costs twice as much). For 64GB Extreme micro sd card it should have read:
(2) Up to 60 MB/s read speed; up to 40 MB/s write speed. Based on internal testing; performance may be lower depending on host device, interface, usage conditions and other factors.
See what I said about grading the speed of the cards. Just so they can squeeze a little more money from their customers. BTW I see that Kingston and Lexar are doing 128GB micro sd cards now.

gandalf_grey91 said:
Two quotes from the Sandisk legal statement about Extreme 64GB micro sd card:
2) Card only. Up to 80 MB/s read; up to 50 MB/s write. Based on internal testing; performance may be lower depending upon host device.
(4) UHS Speed Class 3 designates a performance option designed to support real time video recording in U3-enabled host devices.
---------- Post added at 11:41 PM ---------- Previous post was at 11:26 PM ----------
Sorry, previous numbers were for 64GB Extreme Plus micro sd cards (Costs twice as much). For 64GB Extreme micro sd card it should have read:
(2) Up to 60 MB/s read speed; up to 40 MB/s write speed. Based on internal testing; performance may be lower depending on host device, interface, usage conditions and other factors.
See what I said about grading the speed of the cards. Just so they can squeeze a little more money from their customers. BTW I see that Kingston and Lexar are doing 128GB micro sd cards now.
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I emailed my seller and he posted pretty much the same thing, and said my card was well within the normal operating speeds, and a replacement wouldn't make it any better.
I'm getting 51MB/s read and 33MB/s write nowadays. Guess something was running on the background back then.
Guess I'll have to live with it. It ain't too bad, and random 4k is better than the Samsung one
Tapatalked thru my CM12 G3!

The Extreme cards will get 40-50 but the Extreme Plus get around 80. The newer Pro gets 95. Its obvious Sandisk is inching forward trying to create a new product with a +$100 price point. I got lucky during the holidays and scored my 64gb Extreme Plus during the holidays for $30

xlxcrossing said:
The Extreme cards will get 40-50 but the Extreme Plus get around 80. The newer Pro gets 95. Its obvious Sandisk is inching forward trying to create a new product with a +$100 price point. I got lucky during the holidays and scored my 64gb Extreme Plus during the holidays for $30
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Now that was a deal. I got my Extreme 64GB for what would be 90 US Dollars. That's the price around here unfortunately.
I've contacted again my seller and he seems to be okay with swapping my card. I ran the SD test three times for each of my 64GB cards to see how they would fare.
As expected, the Samsung has a higher read speed, but minimum write (Class 10, Minimum 10MB/s write speed, as I've read).
The SanDisk Extreme has a slightly lower write speed than what I thought would be 30MB/s, but nothing too bad. But read speeds are not that good, compared to a lower-end rival card.
http://imgur.com/a/KNGpT