Does anyone know the specific read and write megabytes per second limitations of our cpu's? More specifically i am wondering if we would benefit from a class 10 or if anything beyond a class 6 or are we wasting our money cuz the phone's cpu cant match the read and write speeds of a class 10. Also does anyone know how accurate sd card speed tester app is? I used it and it said with the stock class 2 sd card that it was reading 13mb per sec and writing 7mb per sec. If that is accurate then to my knowledge We would benefit from atleast a class 6 or higher.
I've looked for specs on this as well, but can't find anything, just that the max size supported is 32gb microsdhc. ;\ Would you really want to spend the money on a Class 10 card, though? $90 bucks for 16gb? No danke.
jbadboy2007 said:
Does anyone know the specific read and write megabytes per second limitations of our cpu's? More specifically i am wondering if we would benefit from a class 10 or if anything beyond a class 6 or are we wasting our money cuz the phone's cpu cant match the read and write speeds of a class 10. Also does anyone know how accurate sd card speed tester app is? I used it and it said with the stock class 2 sd card that it was reading 13mb per sec and writing 7mb per sec. If that is accurate then to my knowledge We would benefit from atleast a class 6 or higher.
Click to expand...
Click to collapse
The CPU itself would not be the limiting factor.
One tip: Sandisk's most expensive Class 10 flash is NOT the fastest for random-access reads. I've seen benchmarks done in multiple places that show that other brands (mostly sold by Newegg, nothing you can even fantasize about buying in a major retail store) are up to 50% faster.
The paradox is because "class" measures ONLY write speeds, but the way most guys here use it is as a fake hard drive in ways that are more read-intensive. Sandisk's target market isn't performance-oriented owners of high-end Android phones. Their target market is video professionals who only care about reliability and storage-life. As a result, if they have to choose between optimizing for long-term data integrity and raw blazing performance, they'll go for integrity every time as long as write performance is fast enough to meet the standard.
If you're going to walk into a store like CompUSA/TigerDirect and buy flash without reading reviews, your best bet is probably class 6. It's dirt cheap compared to class 10, and isn't much slower than average-benchmarking class 10 when it comes to reads. More to the point, it's cheap enough that if you strike out, you can chuck it and buy a more carefully-researched second card online without hating yourself for the next year. If you spend $15-20 on a mediocre class 6 4-gig card, it's not a big deal. If you spend $120+ on a mediocre class-10 16-gig card, you're basically stuck with it for the next 2 years unless you can unload it on somebody who doesn't know better.
write speeds are the more intensive and slower than read speeds. Kingston sells their products based upon write speeds. sandisk sells upon read speeds. kingston class 10 sd card equals 10 mb write speeds 19 mb read speeds sanddisk class 10 is 10 mb read and 7-8mb write speeds. it takes longer to write data and takes more cpu use. the write speeds are your priority.
Class 10
I have a class 10 Sandisk and it sucks in the nexus one
for some reason if I use the card in a reader it perform ok (10MB WRITE) but in the phone it is painfully slow... and this is true either testing with an SD card test app or by hooking thru the usb cable, so something is wrong and I am not sure it's 100% the card since it perform ok in a card reader...
Doing the same with a class 2 card is transparent, same performance from any interface (USB, Internal).
I have made some test with cluster size if 4K, 16K, 32K and it's the same... The only difference is the card themself, I know they use a new SDHC 3.0 standard, maybe this is the reson why they under perform in the nexus...
jbadboy2007 said:
write speeds are the more intensive and slower than read speeds. Kingston sells their products based upon write speeds. sandisk sells upon read speeds. kingston class 10 sd card equals 10 mb write speeds 19 mb read speeds sanddisk class 10 is 10 mb read and 7-8mb write speeds. it takes longer to write data and takes more cpu use. the write speeds are your priority.
Click to expand...
Click to collapse
You are right in regard to write being more intensive than read, especially for MLC flash but AFAIK Class are part of the SD Card standard and are based on WRITE Speed, can you point out where you take this "difference" between 2 major brand, I am not a sandisk fanboy (far from it) but I doubt this is based on anything real...
actually i read in wikipedia that sandisk sells thier products by read speed and kingston sells thier products by write speed.
It's been awhile since I looked at the spec, but the class is the minimum write speed to earn that spec. Most cards seem to exceed this. The only real way to find out real speeds is via independent tests.
Sent from my SPH-D700 using Tapatalk
Are the only 32 gb cards available Class 2? I haven't found anything faster.....
Related
Currently I'm running a 16gb class 2 that I've had since the 16gb's have been out.(used in my Nokia N800) I found a 16GB class 4 on sale in town for $69 where a class 6 is $120. My question since it hasn't been confirmed (or I suck at searching) does the Magic actually take advantage of the class 6 or with the class 4 be good enough? Thanks for any info on this.
Clinton
IMHO I think your better off with a 16gb class 6, as it is recommended for many hacks Android related. Also you could probably find it cheaper online unless Monet is not an issue.
Just rather buy in town, not a big online buyer. I've read that the class 6 is the only way to go for apps 2 SD and the like but I just wanted to have faster access times to music, video and pictures really. That's pretty much all I have on the card, maybe a few docs but nothing I need to access quickly. If the music/video player or Quick office wont see/use the extra speed increase I'd rather save the cash for a nice set of headphones or case etc..
Clinton
Well the classes indicate how fast the SD card is. Class 2 = 2 MB/s, Class 4 = 4 MB/s and so on, so you would feel a difference between the two.
Cheesebaron said:
Well the classes indicate how fast the SD card is. Class 2 = 2 MB/s, Class 4 = 4 MB/s and so on, so you would feel a difference between the two.
Click to expand...
Click to collapse
Very useful. I know the difference between card speeds, what I was asking is if the Magic can take advantage of the speed increase or is there a limit? I know in using my Nokia N800 (Linux OS) even the moded kernel only took advantage of the class 4 cards and there was no benefit to the class 6.
Clinton
The SD Speed Class Ratings specify the following minimum write speeds based on "the best fragmented state where no memory unit is occupied":
Class 2: 2 MB/s
Class 4: 4 MB/s
Class 6: 6 MB/s
The Class system is a minimum speed that it should perform at, if you are lucky it will work closer to the next class speed, as most cards actually perform faster then their class.
I have an 6GB class 4 sdhc card and the transfer speed is generally around 9-11 mb/s.
If you are putting a swap file on to your sdhc, a class 4 should be a minimum class you are to look for.
Personally, I use Crystal DiskMark to test the write-transfer-speed of my cards. http://crystalmark.info/software/CrystalDiskMark/index-e.html
id242 said:
The SD Speed Class Ratings specify the following minimum write speeds based on "the best fragmented state where no memory unit is occupied":
Class 2: 2 MB/s
Class 4: 4 MB/s
Class 6: 6 MB/s
The Class system is a minimum speed that it should perform at, if you are lucky it will work closer to the next class speed, as most cards actually perform faster then their class.
I have an 6GB class 4 sdhc card and the transfer speed is generally around 9-11 mb/s.
If you are putting a swap file on to your sdhc, a class 4 should be a minimum class you are to look for.
Personally, I use Crystal DiskMark to test the write-transfer-speed of my cards. http://crystalmark.info/software/CrystalDiskMark/index-e.html
Click to expand...
Click to collapse
Thanks I know the speed rating and how they are tested.
I'm not going to be putting a swap on the card or doing apps2sd, it's a Rogers Magic doesn't need either.
Thanks for the link to the speed test, didn't have one.
Does your class4 card give you any troubles at all or have you found it to be up to pare in all your storage needs? Thanks for the reply.
Clinton
Clinton, I mostly use the spare ion for simple photo taking, jotting-down notes and listening to podcasts (via meridian)/streaming radio (via stream furious) in my car. I haven't ever had any problems with it's speed.
I've had the stock 2gb in it for about 2 weeks, then a kingston 6GB class 4 in it for about a month and just this afternoon, picked up a polaroid 8gb class 6 (for $17.99 from Fry's Electronics - in-store).
the only time I have really had any problems with the speed of microsd card was when using them on my DS through r4 or supercard flashcarts. but that was back when 2gb microsd was just hitting the market (that 2gb kingston microsd from verizon was $99. in the USA, verizon was the first to publically sell this size card)
I generally try to stay away from class 2 cards just as one would try to stay away from USB 1.x devices.
without installing any additional software, a quick and simple test to check if the card is quick enough for heavy usage on your phone, might be to test if Vista/Win7 will accept it as ReadyBoost Compatible.
I'm looking to buy a new MicroSD and wondering if getting a class 10 over a class 6 would make a significant difference to the phone (if im using data2sd and or apps2sd)
Thank you!
I think the difference between class 6 and 10 would feel minor, where-as the difference between the class 2 and class 6 feels huge.
And since this is the Vibrant forums, I should mention that the internal memory in the phone is very fast. I tested it at over 10MB/s write on my first phone. My second phone its closer to 6 MB/s write. So you apps and stuff should run perfectly fine from the internal app storage.
I should also mention that I purchased the new kingston micro sd thats rated class 4 but claims speeds upto class 10. Upon testing that I got 9 MB/s write. ($28 after $10 reward from buy.com). My previous class 2 16GB card tested it 2.6 MB/s write for comparison.
Shane_pcs said:
I think the difference between class 6 and 10 would feel minor, where-as the difference between the class 2 and class 6 feels huge.
And since this is the Vibrant forums, I should mention that the internal memory in the phone is very fast. I tested it at over 10MB/s write on my first phone. My second phone its closer to 6 MB/s write. So you apps and stuff should run perfectly fine from the internal app storage.
I should also mention that I purchased the new kingston micro sd thats rated class 4 but claims speeds upto class 10. Upon testing that I got 9 MB/s write. ($28 after $10 reward from buy.com). My previous class 2 16GB card tested it 2.6 MB/s write for comparison.
Click to expand...
Click to collapse
Just to help out here...
the difference between class 2 and class 6 is the exact same as class 6 and class 10. Remember the cd-rom speeds (52x, etc)? That's how the speed is calculated for a SDHC card. So a class 2 = 2x cdrom, class 6 = 6x, class 10 = 10x.
whether our hardware has capability to handle what a class 10 can do, that I don't know. I'd definitely advise to get something with more space than a 2GB card though - I'm not sure everyone needs a 32 (personal opinion/long discussion), but I absolutely agree it should be improved upon.
designerfx said:
Just to help out here...
the difference between class 2 and class 6 is the exact same as class 6 and class 10. Remember the cd-rom speeds (52x, etc)? That's how the speed is calculated for a SDHC card. So a class 2 = 2x cdrom, class 6 = 6x, class 10 = 10x.
whether our hardware has capability to handle what a class 10 can do, that I don't know. I'd definitely advise to get something with more space than a 2GB card though - I'm not sure everyone needs a 32 (personal opinion/long discussion), but I absolutely agree it should be improved upon.
Click to expand...
Click to collapse
I understand that, thats why i picked those classes. But my point is that a class 6 card is 3x the speed of a class2 where class 10 isnt even twice as fast as the class 6. So the perceived difference is smaller, even though the technical difference is the same.
I'm still running a class 2 and I've been wondering if this is holding me back on this phone (card was previously in my G1).
Will the lower classes function the same (creating ext2 etc...) it's just a matter of speed? Just wondering if there's anything that simply can't be done with a class2 or even 6 that could be done with a 10.
CapitalM3 said:
I'm still running a class 2 and I've been wondering if this is holding me back on this phone (card was previously in my G1).
Will the lower classes function the same (creating ext2 etc...) it's just a matter of speed? Just wondering if there's anything that simply can't be done with a class2 or even 6 that could be done with a 10.
Click to expand...
Click to collapse
Just cost you more. Do you really need a class 10 for this phone? Avatar is on a card that isnt even a class 2.
Vegastouch said:
Just cost you more. Do you really need a class 10 for this phone? Avatar is on a card that isnt even a class 2.
Click to expand...
Click to collapse
xD What class was the stock sd card?
I only ever see class 6+ cards being used in higher end compact cameras and SLRs.
Putting anything higher than class 6 in a phone your using for apps/music/movies isn't needed and just a waste of money.
I've also seen a lot of people saying the memory card speeds with the galaxy s are bottlenecked right now, so your not even going to get top speeds with a class 6.
Vegastouch said:
Just cost you more. Do you really need a class 10 for this phone? Avatar is on a card that isnt even a class 2.
Click to expand...
Click to collapse
While the card isn't marked, it tests out at just over 4MB/s which would put it in a class 4.
And we should be clear that the class refers to the write speed. A class 2 will read at 10 MB/s just like the other classes. Where you run into issues with class 2 cards is when you start modding or running programs from the sd card. If you use the card for a swap partition or something the write speed now plays a major factor in the usefulness.
If all you want it for is to place your music files on there and listen to them, then a class 2 will be plenty. That was my initial thought when I bought my 1st 16 GB card for my mytouch3g. Then I got into custom roms and found myself limited.
How do you test the speed of the SD card?
What size microsd card are you looking for? If its a 32GB, I have only seen a Sandisk microsd in Class 2. As far as I know there are no higher classes at this time. Hopefully that will change soon. I would like to get all of my music onto one 32gb card.
designerfx said:
Just to help out here...
the difference between class 2 and class 6 is the exact same as class 6 and class 10. Remember the cd-rom speeds (52x, etc)? That's how the speed is calculated for a SDHC card. So a class 2 = 2x cdrom, class 6 = 6x, class 10 = 10x.
whether our hardware has capability to handle what a class 10 can do, that I don't know. I'd definitely advise to get something with more space than a 2GB card though - I'm not sure everyone needs a 32 (personal opinion/long discussion), but I absolutely agree it should be improved upon.
Click to expand...
Click to collapse
This isnt exactly true. with cdroms the X stands for how much faster it would spin in relation to a audio cd. So 1x ment it spun at the same speed as a audio cd. 2x was twice, ext ext. And this was a max speed.
Classes for SDCard stands for the minimum transfer speed. class two is at least 2mbps, class 6 is 6mbps, and so on.
frankencat said:
How do you test the speed of the SD card?
Click to expand...
Click to collapse
google FDbench
it will test the read and write speed as well as operations per second.
I still can't find a 32gb microsd class 10, anyone find one for sale?
Class 10
Class 10 limitation presently is 8 gig for all brands except the Kingston and soon to be released Silicon Power. The Kingston brand never benches as advertised, so they are not reliable from my point of view. Silicon power has been pretty solid on their claims from my testing versus their claims, but I have not yet got my hands on the latest class 10 16 gig, I have been trying to buy for the since 10-1-2010 but not out in USA yet.
Kingston (in my opinion) is rife with false claims and I find their products have always been sub par.
Flashing and alike works better with class 6 over class 2 & 4. So, if you really want more memory the only 32 gig class 6 I have seen advertised (amazon) are: Transcend, Centon, and Komputerbay (what a name?!) 32 gig Class 6
Other than that, we wil just have to wait until they get the algorithm figured out for a micro ad card with that much ram and that fast.
Get the app "sd card speed test" it works ok Im sure there are others as well
I imagine the only reason you would need a Class 6 card or above is if you plan to take a lot of HD video. Apart from that, even a Class 2 is fast enough to keep up with the still camera, not to mention anything that just requires reads, like music or movie playback.
As for running apps off an external SD card, why would you ever want to do that? You can load close to 2GB on the internal app space, which is likely way faster than any mounted external SD card. I feel like an app whore and I'm not even close to using half that space. By the time apps start getting large enough that it's an issue, we'll be on the Vibrant 2 or beyond.
glad that you asked
merrifield69 said:
I'm looking to buy a new MicroSD and wondering if getting a class 10 over a class 6 would make a significant difference to the phone (if im using data2sd and or apps2sd)
Thank you!
Click to expand...
Click to collapse
because I just picked up a 16G class 10 by WinTec last week and it is VERY fast from boot up with 9G occupied from 15G available (wondered 1G gone to? and that is a lot of gone G lol). It was $42 wo tax expensive but so far the fastest.
Whoohoo
mine 16G class 10 tested 2x >8M and 1x >9M write, 3x > 18M read and it was probably so fast that the result said "unknown class" lol. x means 1 run with 2MB buffer setting. Downloaded app call SD card speed tester.
There are now some 32GB class 6 SDCARDS on the markey, and with 2.2 and installing apps to SD that might matter. It might also matter if you have a TON of music and images, as "Scanning SD for Media" would be faster.
You will pay money for the time savings though.
So I downloaded this app call H2testw.exe to test for legit sdcards but it also tells the read/write speed as well. I am testing my 8gb and 1gb cards. I set it to write a 300 mb files to the card and verify it.
Info about Android running on the two cards:
8gb = lags coming out of sleep, touch screen freezes, write~7.5 mb/s, read~12mb/s
1gb = no lags, no touch screen, write~4.3mb, read~13mb/s
I'm confused. The read speed is almost the same yet the 1gb microsd is more responsive running MDJ android compared to the 8gb microsd. Any thought?
UPDATE: Maybe this is what's causing the problem. Stolen from Engadget.
What we've learned from our tipsters and from documents culled from Microsoft, Samsung, and others is that the big issue is random access performance -- a figure that isn't taken into account in a card's class rating. Ironically, Microsoft discovered in its testing that cards with higher class ratings actually performed worse on Windows Phone 7 because the tweaks card manufacturers make to achieve high sequential throughput can actually hurt random access times. There's some rocket science involved here, but basically, it's a tradeoff and a bit of a gamble -- if a manufacturer tunes a card for a high class rating, it takes more time to access the first byte at a new location on the card because it's optimizing access for that area of memory, but once it does that, it can blast sequential bytes at very high speed. If you've got a lot of small reads or writes you need to make to different files at different locations in the card's memory, though, you really start to suffer. Cards with lower class ratings tend to spend less time optimizing sequential access prior to the first read / write operation, so it can move around the card (that is, access it randomly) much faster.
Click to expand...
Click to collapse
Source:
http://www.engadget.com/2010/11/17/windows-phone-7s-microsd-mess-the-full-story-and-how-nokia-ca/
They are probably different classes, plus it naturally takes longer with a bigger card because there's more files and more space to read and write
Sent from my HD2 Nexus One using XDA App
I get screen freezes with 8gb and up but rarely with new builds, haven't tried a card higher than class 6
Also I'm on radio 2.15
Sent from my HD2 Nexus One using XDA App
Oddly enough, I have two 8gb cards, one class 4 the other class 6, and they hiccup more than my 16gb class 2.
Now that is weird.
I'm lost myself...I'm thinking off just getting me a 4gb card and hope for the best...
I heard the 16gb class 10 is perfect but it still cost to much for nand to be around the corner
Sent from my HD2 Nexus One using XDA App
16 gb class 10 no lag cost me over 100 pounds tho
Sent from my HTC Desire using XDA App
Cheapest 16GB - lags from time to time :/
Maybe defragmentation may help?
tomus said:
Cheapest 16GB - lags from time to time :/
Maybe defragmentation may help?
Click to expand...
Click to collapse
Defrag wont help...scan for errors...try to have only the android folder and see if it makes a different ..
Btw, guys...
all sd cards are not created equal. all sd cards of the same CLASS are not created equal.
Check out the ongoing drama with win7 phones with SD slots....
class measures throughput, what affects the SOD and related issues is random access speed, not throughput so much.
It's just my 2 cents, but I've tested Class 2, 4, and 6 MicroSDHC cards and found very little noticeable difference once Android is fully booted up and running on the HD2. Moreover, none of the cards create screen freezes or SOD issues or high battery drain problems here. That said, I have noticed that the actual boot time and file transfer speed (from the PC to the card) can be faster on average with quality higher class rated cards of the same size. Also, I've found that the larger the card size, the longer the android boot time, no matter the class. Guess that makes sense, as the system need to read more sectors with larger size cards. Please note that I've only tested Sandisk, Toshiba, TopRam and Samsung cards to date. What's kind of strange is that the Class 2 16 & 32GB Sandisk cards run just as well or slightly better for some reason than some of my higher class rated cards. Go figure...
As far as issues go, I recommend only using quality brand name cards, no ebay fakes or cheap no name brands. Also, I've had great luck formatting all my cards with SD Formatter v2.0 and v3.0, using the quick format mode with the standard 32kb cluster size.
Best to all,
R
rhacy said:
It's just my 2 cents, but I've tested Class 2, 4, and 6 MicroSDHC cards and found very little noticeable difference once Android is fully booted up and running on the HD2. Moreover, none of the cards create screen freezes or SOD issues or high battery drain problems here. That said, I have noticed that the actual boot time and file transfer speed (from the PC to the card) can be faster on average with quality higher class rated cards of the same size. Also, I've found that the larger the card size, the longer the android boot time, no matter the class. Guess that makes sense, as the system need to read more sectors with larger size cards. Please note that I've only tested Sandisk, Toshiba, TopRam and Samsung cards to date. What's kind of strange is that the Class 2 16 & 32GB Sandisk cards run just as well or slightly better for some reason than some of my higher class rated cards. Go figure...
As far as issues go, I recommend only using quality brand name cards, no ebay fakes or cheap no name brands. Also, I've had great luck formatting all my cards with SD Formatter v2.0 and v3.0, using the quick format mode with the standard 32kb cluster size.
Best to all,
R
Click to expand...
Click to collapse
Great info here. I think I will just order me a new card from a reputable brand. Maybe my card is just getting old. Maybe a 16gb from Amazon will do. They aren't too expensive nowaday. ~$26.
Does the Radio version effects the lag of the sd card? Or the kernel?
distruct said:
Does the Radio version effects the lag of the sd card? Or the kernel?
Click to expand...
Click to collapse
No, not on the sd but radio does effect how the build will run, your phone calls, your battery.
Could this be the reason why class don't matter on hd2 android? I mean even some class 4 & 6 have lag and sod problem. I pulled this bit from engadget. It's an article on wp7 and memory card issues.
What we've learned from our tipsters and from documents culled from Microsoft, Samsung, and others is that the big issue is random access performance -- a figure that isn't taken into account in a card's class rating. Ironically, Microsoft discovered in its testing that cards with higher class ratings actually performed worse on Windows Phone 7 because the tweaks card manufacturers make to achieve high sequential throughput can actually hurt random access times. There's some rocket science involved here, but basically, it's a tradeoff and a bit of a gamble -- if a manufacturer tunes a card for a high class rating, it takes more time to access the first byte at a new location on the card because it's optimizing access for that area of memory, but once it does that, it can blast sequential bytes at very high speed. If you've got a lot of small reads or writes you need to make to different files at different locations in the card's memory, though, you really start to suffer. Cards with lower class ratings tend to spend less time optimizing sequential access prior to the first read / write operation, so it can move around the card (that is, access it randomly) much faster.
Click to expand...
Click to collapse
Source:
http://www.engadget.com/2010/11/17/windows-phone-7s-microsd-mess-the-full-story-and-how-nokia-ca/
azzzz said:
Could this be the reason why class don't matter on hd2 android? I mean even some class 4 & 6 have lag and sod problem. I pulled this bit from engadget. It's an article on wp7 and memory card issues.
Source:
http://www.engadget.com/2010/11/17/windows-phone-7s-microsd-mess-the-full-story-and-how-nokia-ca/
Click to expand...
Click to collapse
Obviously.
Been saying this for a while, myself - I have experimented, and I get SOD every time with my 16gb class 6 card, but rarely with my class 2 8gb, and never ever (and, tbh, better responsiveness overall) with my 2gb NON-HC card
enneract said:
Obviously.
Been saying this for a while, myself - I have experimented, and I get SOD every time with my 16gb class 6 card, but rarely with my class 2 8gb, and never ever (and, tbh, better responsiveness overall) with my 2gb NON-HC card
Click to expand...
Click to collapse
I hope so...my class 2 16gb will be here in a couple of days...i hope it's faster than my current 8gb class 4....
Update: my 16gb class 2 sandisk is here. Things have improved alot. Wake up is faster now with less lag, market download speed is faster now (10kb vs 100kb). Hopefully system performance will be better...
I am about to buy another micro sdhc card and was wondering what the big difference between the two would be between the classes. I already know what the classes mean, class 2 means it will write at 2 megabits a secound, where as 10 writes at 10 megabits a secound.
My question is what would that extra speed allow you to do what you wouldn't be able to do before. Where would a fast card really shine. is there a maxamium speed that the phone can run at.
would it be better for running android sd, linux in a virtul machine on android (forgot what that is called) watching movies on sd, or apps, games on sd
i also have a asus transformer 10" honeycomb tablet would that i might use it in.
does anybody know?
Doesn't really make a big difference in running an SD Android build. I've been running multiple SD builds on the 16gb class 2 that came with my HD2 for like 2 years, and it is butter smooth. I've seen people on the HD2 forum who bought class 10 cards and had problems. The standard answer that you'll usually find around here about SD cards is that it's pretty much a hit-or-miss thing.
I personally wouldn't waste my money on a more expensive card just for faster write speed, since it seems like if it makes a difference at all, its a negligable difference.
Class is a measure only used on microsd. It means the sdcard MUST be able to withstand writing to it at 10mb/s. So yeah, a class10 should be better than a class2.
Wikipedia
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 Mbit/s (1 MB/s), the least sustained write speeds for a card in a fragmented state (Class 2, 4, 6) or the minimum non-fragmented sequential write speed (Class 10).
Click to expand...
Click to collapse
In reality...
No one guarantees that the sdcard reader/writer can write to it at the given speed (or even needs to). Also, many times de class is a basic measure. My 16gb class 10 can be written (on a computer) at 21mb/s tops. Many class2/4 can be written at class10 speeds or above. It's just a guarantee. As a user rarely writes data sequentially, a class 6 should be enough, making a class 10 better only when copying LARGE files (ex. mp3) to the card.
Now, i've never seen, and there's no statistic that class X cards are better than class Y. There are brands better than others, but that's it.
BTW, in Android at least (this must apply on other OS's), increasing sdcard cache to 1024 or above (at a maximum of 2048) improves write speed immensely.
Class 10 will give you faster speed when you transfer large files from pc to card ( videos updated gps map etc ) but I also read somewhere that higher class card uses more battery even in standby . Class 4 should be more than good .
budalica said:
Class 10 will give you faster speed when you transfer large files from pc to card ( videos updated gps map etc ) but I also read somewhere that higher class card uses more battery even in standby . Class 4 should be more than good .
Click to expand...
Click to collapse
Make it 6... faster non sequential write speed
Which will give the biggest performance boost? I know it should be a class 10 but I've seen reports that sometimes there isn't that much difference between a class 6 and a class 10.
Is it also true that a class 10 would use more battery than a class 6 (and if so, how much more)?
I'm basically looking at getting a 16gb or a 32gb card and installing vegacomb on it (and later ICS) and want the best performance possible and as long a battery life as possible.
Hi!
Here is a wikipedia link for the classes of SD cards:
http://en.wikipedia.org/wiki/Secure_Digital#Speed_Class_Rating
The higher the class number the better the performance, but if you look at the "Electrical interface" chapter you can read at the end of that chapter, that greater transfer speeds consume more power. But I don't think that much more, the bigger power hog is usually the LCD panel.
Besides, system critical data is stored on NAND and not on microSD.
On microSD are apps, games, music, documents, videos,... (non-important data).
i use a samsung 16gb class 6 card, since class 10 costs too much money. its good card, reliable and very quick. but do note, that these cards speed ratings are for sustained reads and writes of large files. if you read and write small files the performance drops off sharpish and youd be lucky if the cards do a quarter of thier rated max speed.
also take into account the vega/mobii's card reader speed, its not the best but decent class 4 would do the job well.
all depends on how much you want to spend, best price performance i found was with class 6 cards.