Related
I'm buying a larger SD card in readiness for Froyo (and I need more room for music!).
I've already filled up the 4GB card that came with the phone. Is it simply a case of copying everything from the 4GB card onto a computer, inserting the new card and copying it all back? Or is there some funky protection scheme in some app data which will break everything?
Also, will Eclair be able to format the new card (it's 32GB)? I think Windows 7 only formats fat32 on smaller drives.
Any information or other peoples experiences would be welcome.
If you just have one 4Gb partition it is safe to copy all the files to the new one and it should work without problems (copy also the hidden files).
For the format, Windows 7 can format it. Not sure if fat32 or exFat, but it can format it for sure.
Remember to buy a class 6 sdcard.
it will be much faster.
Oby One said:
Remember to buy a class 6 sdcard.
it will be much faster.
Click to expand...
Click to collapse
Just wanted to jump in here to clarify this statement. Higher classes means faster write speeds. There are no difference in read speeds.
Therefore...
- Having a higher class card will not result in better performance in tasks like generating thumbnails when viewing photos in your Photo application.
- If your application is installed on your card, higher classes will not mean faster application performance. Again, read speeds are not affected.
- Having a higher class card will mean you will be able to transfer files from your PC to your card faster.
That being said, you should buy the highest class card you can afford. But you should prioritize capacity over speed.
Tip: Pass on class 2 cards. They may start choking when you use your device to record 720p video.
ohyeahar said:
Tip: Pass on class 2 cards. They may start choking when you use your device to record 720p video.
Click to expand...
Click to collapse
Zero problems with my Sandisk 16gb Class 2 card. It writes at a sustaining 7.5mb/s, so faster than Class 6 minimums anyway.
Regards,
Dave
Thanks for all the advice guys.
Regarding the class, it has to be class 2 - it's the only thing available in 32GB.
However, as ohyeahar said, it's only write speed. I don't think a 720p stream will be a problem given the benchmarks I've seen for the Sandisk 32GB card. It seems to be writing at 5-7Mb/s so well above the Class 2 minimum.
I'm also buying a new microSDHC card. Should I format it in NTFS or FAT32?
Laban said:
I'm also buying a new microSDHC card. Should I format it in NTFS or FAT32?
Click to expand...
Click to collapse
Correct me if I'm wrong but when I format it on my computer, my desire always tells me to do it again anyway on my phone that is
Sent from my HTC Desire using XDA App
lennshow66 said:
Correct me if I'm wrong but when I format it on my computer, my desire always tells me to do it again anyway on my phone that is
Sent from my HTC Desire using XDA App
Click to expand...
Click to collapse
Ah, of course! That must be the correct way of doing it. Thinking of buying the Sandisk Mobile Ultra 16GB or the Transcend Class 6 16GB or A-Data Class 6 16GB.
Any recommendations?
Where is everybody looking to get their memory cards from? I'm currently looking for the best deals and struggling to find any decent ones tbh
ohyeahar said:
Just wanted to jump in here to clarify this statement. Higher classes means faster write speeds. There are no difference in read speeds.
Therefore...
- Having a higher class card will not result in better performance in tasks like generating thumbnails when viewing photos in your Photo application.
- If your application is installed on your card, higher classes will not mean faster application performance. Again, read speeds are not affected.
Click to expand...
Click to collapse
Click to expand...
Click to collapse
I think you are not well informed. Higher class cards also offer higher read speeds and that is very important.
In my phone applications are also writing to card so having a higher class card makes all the difference. especially if you are using it with a swap partition.
I don't have the link to the benchmark right now but I will show you tomorrow the different read/write speeds in different class cards
Therefore...
- Having a higher class card will not result in better performance in tasks like generating thumbnails when viewing photos in your Photo application.
Click to expand...
Click to collapse
Yes it will
- If your application is installed on your card, higher classes will not mean faster application performance. Again, read speeds are not affected.
Click to expand...
Click to collapse
yes it will
later edit:
I don't remember exactly the values for read speads but from my tests they were something like this
cls2 15mb/sec
cls4 18mb/sec
cls6 21mb/sec
for me ...speed is everything so class 6 it's my choice
Oby One said:
I think you are not well informed. Higher class cards also offer higher read speeds and that is very important.
Click to expand...
Click to collapse
Sorry, but that just isn't the case!
The class of an SD card is purely the minimum sustained write speed that the card will achieve in a completely unfragmented state. It has *nothing* to do with read speeds.
Case to point, here are the benchmarks for two of my MicroSD cards:
16gb Sandisk Class 2
Sequential Read : 20.050 MB/s
Sequential Write : 7.415 MB/s
8gb Transcend Class 6
Sequential Read : 19.938 MB/s
Sequential Write : 15.020 MB/s
Note that the read speeds are almost identical, but the write speed of the class 6 is almost twice the amount. However, the write speed of both cards is well in excess of the class 6 minimums and given that there's far less writing going on than reading, the difference in write speed is practically negligible on the Desire.
Which card do I used in my Desire? The 16gb Class 2 and I experience absolutely no lag whatsoever using my phone, and I'm using Froyo Apps2SD.
Regards,
Dave
Laban said:
I'm also buying a new microSDHC card. Should I format it in NTFS or FAT32?
Click to expand...
Click to collapse
fat32
10 chars
Hmm, maybe because it's a newer generation class 2 card?
perhaps my tests were done with older generation cards that gave out lower speeds.
Now I am curios...I can't wait to get back home and find the tests file.
foxmeister said:
Sorry, but that just isn't the case!
The class of an SD card is purely the minimum sustained write speed that the card will achieve in a completely unfragmented state. It has *nothing* to do with read speeds.
Click to expand...
Click to collapse
Yep, Dave is absolutely right, it's purely minimum sustained write speed for that class. And as you can see, his Class 2 card actually exceeds the class 6 spec for writing and isn't far off from Class 8 performance.
Looking around the web, the 32GB class 2 card I bought has similar performance in the benchmarks I've seen to Dave's Class 2 card. Not only that, the benchmarks are done on a PC. I doubt the phone has the I/O bandwidth to actually hit numbers like those in any kind of sustained way.
ok, my bad.
There is a slight difference between different brands (regarding read speed) but not so big.
regarding write speed .... I think that only if you use your sdcard with a swap partition you will see big differences.
Has anyone tried this app? Been having issues with music cutting out when sd card is in use since upgrading to 2.2. So I thought i`d run this test as I have a transcend 8gb class 6 card. This app is reporting I have a class 2!?
My results are
write speed 3.0 mb/sec
read speed 7.0 mb/sec
Anyone else care to share their results, would like to know if this app is wrong or i`ve got a fake card.
Thanks
Just tried out the app and it says I have a class 4 card with a write speed of 5mb/s and read of 6mb/s though its rated at being a class 6 Transcend. I've got access to some other cards at work so I'll try them out as well. Might help to defrag?
Sent from my HTC Desire using XDA App
Thanks, actually I re-booted and closed down all non-essential apps and I got a 6mb/sec read/write saying it was a class 6.
But looking round the web people are reporting 10mb+ /sec on a class 6
Hv installed the app and made 3 tests successively for my 16Gb sandisk Class2 sd-card, said "Class2" as expected (second test resulted "ClassUnknown" and read speed was nil) anyway, overall result is;
Write speed: 2 Mb/s
Read speed: 1 Mb/s (!)
I thought read speed would be twice as much than the write speed; confused & disappointed!
Sent from my HTC Desire using XDA App
Getting the same problem with music skipping. Annoying as hell and only started since updating to 2.2
If you read what it says as tip 2 down the bottom, a class 6 card means a minimum read/write speed of 6mbps so it wouldn't be uncommon to see a higher read/write speed for the card. Wonder what a format would do for it.
Sent from my HTC Desire using XDA App
paulruk said:
Has anyone tried this app? Been having issues with music cutting out when sd card is in use since upgrading to 2.2. So I thought i`d run this test as I have a transcend 8gb class 6 card. This app is reporting I have a class 2!?
My results are
write speed 3.0 mb/sec
read speed 7.0 mb/sec
Anyone else care to share their results, would like to know if this app is wrong or i`ve got a fake card.
Thanks
Click to expand...
Click to collapse
Same card, same results.to get class 6 results you must haver perfect conditions and sequential write. Reading can usually be higher. I'm not sure, but I think it also deteriorates with time.
Ive got a 16gb Play.com Card and had the card for about 2 years now.
Its says class 2 on the card but i get the following.
1st test, Class 2
2nd test, Class 4
3rd test, Class 4
4th test, Class 4
CharlieCharlie24 said:
Getting the same problem with music skipping. Annoying as hell and only started since updating to 2.2
Click to expand...
Click to collapse
Yeah, and theyve screwed up web browsing. Think i`d rather have 2.1 back.
Jabbafat23 said:
If you read what it says as tip 2 down the bottom, a class 6 card means a minimum read/write speed of 6mbps so it wouldn't be uncommon to see a higher read/write speed for the card. Wonder what a format would do for it.
Sent from my HTC Desire using XDA App
Click to expand...
Click to collapse
Well looking at this thread http://androidforums.com/htc-evo-4g/86850-htc-evo-4g-sd-card-speed-test.html
Someone has the same card as me but getting 10mb/sec read & write. Albeit on an htc evo. But cant think it would make any difference.
It should also make sense that A2SD and Dalvik Cache to SD even more, will impact the test, no matter how much you close and kill processes before running the test.
For 720p purposes, I'd like to know if anyone who had problems with the stuttering (not low fps, but the frozen frame now and then), solved this with an upgrade in class and if it's really needed a class 10. Again, A2SD+ can be a factor in this.
Anyway, I've tried a cheap sandisk class2 16GB:
- first run, everything on, auto screen off: read 2MBit, write 3Mbit -> class 2
- second run, airplane on, auto screen off: same
- third run, killed everything, screen always on: read 6Mbit, write 3Mbit -> class 2
- fourth run, as above: same results
The interesting bit is that my transcend class 6, 8GB one, had very very similar results, with bumps to 4Mbit write right after boot, when killing everything...
That's what makes me hesitate to buy a class 10 card. Will the actual usage speed improve so much to justify the cost, especially on 720p ?
andycted said:
It should also make sense that A2SD and Dalvik Cache to SD even more, will impact the test, no matter how much you close and kill processes before running the test.
For 720p purposes, I'd like to know if anyone who had problems with the stuttering (not low fps, but the frozen frame now and then), solved this with an upgrade in class and if it's really needed a class 10. Again, A2SD+ can be a factor in this.
Anyway, I've tried a cheap sandisk class2 16GB:
- first run, everything on, auto screen off: read 2MBit, write 3Mbit -> class 2
- second run, airplane on, auto screen off: same
- third run, killed everything, screen always on: read 6Mbit, write 3Mbit -> class 2
- fourth run, as above: same results
The interesting bit is that my transcend class 6, 8GB one, had very very similar results, with bumps to 4Mbit write right after boot, when killing everything...
That's what makes me hesitate to buy a class 10 card. Will the actual usage speed improve so much to justify the cost, especially on 720p ?
Click to expand...
Click to collapse
I've had stuttering with video and my class 6 8gb transcend. I never use to, I blame 2.2
For that too. So much for a speed improvement , only thing that feels.quicker in 2.2 are app installs.
For reference, if anyone is interested:
HTC Desire, unbranded, generic Froyo 2.2 ROM with apps on the SD card as well
Sandisk 32GB Class 2 card shows:
Write speed: 4mb/s
Read speed: 2mb/s
Measured as a Class4 card.
removed
Kingston 16GB MICROSDHC CLASS 2:
Write 5MB/s
Read 16MB/s
Using: Galaxy S
Buffer: 1MB
Samsung 8gb class 6
Write 2mb
Read 6mb
I'm running a2sd+ though...
Sent from my HTC Desire using XDA App
Don't defrag non-mechanical memory devices
1 - you won't see (or measure) any difference
2 - the memory cells have a limited # of write cycles, which will be seriously impacted by useless defragging
I had the same problem as the OP (slow SD since Froyo upgrade causing music dropouts). Here's my collection of links to related posts, unfortunately I haven't found a solution except using a non-Sense ROM (e.g. Cyanogenmod).
http://forum.xda-developers.com/showthread.php?t=781606#9
http://forum.xda-developers.com/showthread.php?t=743792
http://forum.xda-developers.com/showthread.php?t=778748
http://forum.xda-developers.com/showthread.php?t=723073
I think it's kernel-related; I tried running the kernel from a Froyo/Sense ROM with the rest of an Eclair/Sense ROM and the SD card read speed was low (couldn't measure the speed with the SD Card Speed Test app because the touchscreen didn't work but I was able to adb in and use "dd").
Since a number of us are experiencing this problem I think it's worth us all reporting it to HTC support. If they know that a lot of people are seeing much worse SD card speeds in 2.2 than in 2.1 then they're more likely to fix it in a future update.
I've reported it to them already
Read 10MB/sec
Write 5MB/sec
It rated it as a class 4 card(Which it is), I'm quite surprised at that performance since I bought it for hardly 5$.
Hey
A while back I was looking for a 64GB microSDXC card but sadly I couldnt find any. Ill have to sacrifice and go for a 32GB microSDHC Class 10.
So which is the best (performance and price) 32GB microSDHC Class 10?
Thanks for all the help and suggestions.
how about this
http://www.amazon.co.uk/KOMPUTERBAY...?s=electronics&ie=UTF8&qid=1302552312&sr=1-22
OR
http://www.amazon.co.uk/Storage-Opt...?s=electronics&ie=UTF8&qid=1302552419&sr=1-33
loads more on amazon
tvr84 said:
how about this
http://www.amazon.co.uk/KOMPUTERBAY...?s=electronics&ie=UTF8&qid=1302552312&sr=1-22
OR
http://www.amazon.co.uk/Storage-Opt...?s=electronics&ie=UTF8&qid=1302552419&sr=1-33
loads more on amazon
Click to expand...
Click to collapse
Doesn Amazon uk ship worldwide?
riahc3 said:
Doesn Amazon uk ship worldwide?
Click to expand...
Click to collapse
No, where do you live?
Pokerface1987 said:
No, where do you live?
Click to expand...
Click to collapse
I live in Europe.
riahc3 said:
MOD EDIT: NO EBAY LINKS
Click to expand...
Click to collapse
My apologies Did not know that rule.
More help would be appreciated as Im trying to get all the "parts" to finally complete my mobile purchase
just check the chinese sites like dhgate, dealextreme etc and pay with paypal. sometimes they send fake ones so i would recommend running this program. it will tell you the speed of your read/write so you know the true class and how much actual room it has
http://forum.xda-developers.com/showthread.php?t=1026536
lorijuan1024 said:
just check the chinese sites like dhgate, dealextreme etc and pay with paypal. sometimes they send fake ones so i would recommend running this program. it will tell you the speed of your read/write so you know the true class and how much actual room it has
http://forum.xda-developers.com/showthread.php?t=1026536
Click to expand...
Click to collapse
The problem is that by the time I recieve the card and see that it is fake, I have to send it back (problably pay S&H) then I get my money back...
2-3 weeks. I want something that works period.
riahc3 said:
The problem is that by the time I recieve the card and see that it is fake, I have to send it back (problably pay S&H) then I get my money back...
2-3 weeks. I want something that works period.
Click to expand...
Click to collapse
on ebay they just send another one to not get bad feedback and most likely send the right one or refund the money back and then you get a free sd card out of it
lorijuan1024 said:
on ebay they just send another one to not get bad feedback and most likely send the right one or refund the money back and then you get a free sd card out of it
Click to expand...
Click to collapse
This is assuming there is a problem on eBay. Ive bought several products on eBay and have NEVER had a problem. You just have to know how to buy.
My problem is now knowing which to buy as I just know a few and only the Topram one is avaliable on eBay.
If you're using this for a phone, you may not want a class 10. A class 2 or 4 Sandisk may be better for you. Depends what you're using it for.
Class 10 gives fast sequential speeds, but it usually sacrifices random read, write and access speeds. I could go into the reason why this happens, but I've posted several times about that, so you can check my previous posts for that.
Class 10 is good for digital cameras or other things where sequential speed is important and random speeds aren't important. If you're using the card to run apps off of, or system files for Android, or any OS actually, or using it for WP7, or anything that will need sequential speeds and fast access times, class 10s are slower than good quality class 2 or 4 cards like Sandisk.
Higher class DOES NOT mean better or faster for everything. Class only refers to sequential write speed. Different types of cards are better and faster for different tasks. Class 10s will many times slow down or cause lag in phones, depending on how the phone uses it. Sandisk class 2 and 4 cards I have found to be the best all around cards for phones.
zarathustrax said:
If you're using this for a phone, you may not want a class 10. A class 2 or 4 Sandisk may be better for you. Depends what you're using it for.
Class 10 gives fast sequential speeds, but it usually sacrifices random read, write and access speeds. I could go into the reason why this happens, but I've posted several times about that, so you can check my previous posts for that.
Class 10 is good for digital cameras or other things where sequential speed is important and random speeds aren't important. If you're using the card to run apps off of, or system files for Android, or any OS actually, or using it for WP7, or anything that will need sequential speeds and fast access times, class 10s are slower than good quality class 2 or 4 cards like Sandisk.
Higher class DOES NOT mean better or faster for everything. Class only refers to sequential write speed. Different types of cards are better and faster for different tasks. Class 10s will many times slow down or cause lag in phones, depending on how the phone uses it. Sandisk class 2 and 4 cards I have found to be the best all around cards for phones.
Click to expand...
Click to collapse
Thanks for the explanation but I knew most of this information
The reason I want a Class 10 is that pictures are taken/saved alot faster. Thats pretty much the only reason.
A additional plus is that transfering media thru the cable is also faster.
Ok, well those are probably the 2 biggest reasons to use class 10... using with digital camera and fast transfer speed.
I just wanted to make sure you were getting the right card for what you were using it for. The majority of people seem to basicly think that higher class = better automatically, and don't understand different cards are better for different purposes.
zarathustrax said:
Ok, well those are probably the 2 biggest reasons to use class 10... using with digital camera and fast transfer speed.
I just wanted to make sure you were getting the right card for what you were using it for. The majority of people seem to basicly think that higher class = better automatically, and don't understand different cards are better for different purposes.
Click to expand...
Click to collapse
Yeah I understand thanks anyways.
No more information it seems
zarathustrax said:
If you're using this for a phone, you may not want a class 10. A class 2 or 4 Sandisk may be better for you. Depends what you're using it for.
Class 10 gives fast sequential speeds, but it usually sacrifices random read, write and access speeds. I could go into the reason why this happens, but I've posted several times about that, so you can check my previous posts for that.
Class 10 is good for digital cameras or other things where sequential speed is important and random speeds aren't important. If you're using the card to run apps off of, or system files for Android, or any OS actually, or using it for WP7, or anything that will need sequential speeds and fast access times, class 10s are slower than good quality class 2 or 4 cards like Sandisk.
Higher class DOES NOT mean better or faster for everything. Class only refers to sequential write speed. Different types of cards are better and faster for different tasks. Class 10s will many times slow down or cause lag in phones, depending on how the phone uses it. Sandisk class 2 and 4 cards I have found to be the best all around cards for phones.
Click to expand...
Click to collapse
Very helpful information, zarathustrax!
Didn't know about the random speed part. Thanks for the explanation.
Cayenne Pepper said:
Very helpful information, zarathustrax!
Didn't know about the random speed part. Thanks for the explanation.
Click to expand...
Click to collapse
Related information: http://en.wikipedia.org/wiki/Solid-state_drive
Hit the "Thanks" button if you liked his post
Saw you already did.
Ive (to my surprise) found a Patroit 32GB C10 at a lower price than the Topram.
It looks legit but....you never know.
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.
Click to expand...
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.
Click to expand...
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.
Click to expand...
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
Click to expand...
Click to collapse
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...
Click to expand...
Click to collapse
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?
Click to expand...
Click to collapse
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.
Click to expand...
Click to collapse
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.
Click to expand...
Click to collapse
Cool
I have Sandisk Micro HDSD 16GB Class 2 but in SD Tools Write Speed: 10.1Mb/s, Read Speed: 27.5Mb/s
I just got my new 32GB Class 4 SD card, and was shocked to see that the write speed was nearly half the speed of the SD card that came with the phone, which turned out to be a Class 6. But what confuses me most of all is that a higher class should be faster if I'm correct, and the write speed of my new SD class is slower, but the read speed is actually faster. I'm seriously confused as to if this is what is meant to happen. >.<
Speeds of MicroSD cards tend to fluctuate, especially under the Android environment. You may have tested when the Class 4 was at peak read speeds, and when the Class 6 was at low read speeds
But it wasnt just one test, I tested the Class 6 multiple times and was getting 13 - 14mb read, and the Class 4 got 19mb+
>.<
Did you takes all those tests in a row? Or on separate occasions? My class 6 Sandisk got above 28mbps reads even on Android
Seeing as though you got 28mbps, Im starting to wonder whether my SD cards are faulty, my phone is faulty or something else. >.<
In addition, you'll also see different speeds when using cards of different brands. However, high sequential read/write speeds aren't always what you should be looking for. If you run ROMs from SD or have lots of apps installed to your SD, you should also consider looking at the random read write/speeds as those speeds are more important for those aspects.
If your new sd card is a larger storage it will be slower because it has more data to check through if they are the same size you may have even got a dodgy sd card or fake there is lots of reasons why this can happen and as solar plexus said
Solar.Plexus said:
In addition, you'll also see different speeds when using cards of different brands. However, high sequential read/write speeds aren't always what you should be looking for. If you run ROMs from SD or have lots of apps installed to your SD, you should also consider looking at the random read write/speeds as those speeds are more important for those aspects.
Click to expand...
Click to collapse
Sent from my R800i using xda premium