Database Users

SD cards and their class....

Ive been trying to work some stufff out and im pretty confused....
I have a class 2 sandisk microSD(8GB) and a Kingston class 6 microSD(4GB)
When i copy stuff to and fro i get the same transfer speed varying from 3mbps to 4mbps, I thought that class 6 meant 6mbps? this has annoyed me somewhat as i wanted a fast card|!!

Class 6 cards are faster. How are you transferring your files? Are you mounting your phone and doing it that way? Or are you using a card reader? If I transfer files using my g1 or mytouch, all my memory cards transfer at about the same rate, and I have a class 2, 4, and 6. However, if I use a card reader, my 16GB class 6 transcend blows my class 2 and 4 out of the water in terms of transfer. If I put a hero rom on my memory cards, they can take as long as 20 seconds with my classes 2 and 4. With my class 6, it transfers in about 6 seconds and it's a 80-90 meg file. Hope this helps.

ive tried with both but i will try again with my card reader nd see, Thanks

Disappointing results : 32Gb Class4 Kingston vs Sandisk 16Gb Class 2 microSD

I'm sorry to report that I've returned the Kingston Class 4 32Gb microSD card for its failure to perform.
Performance writing to this Kingston card (from a desktop PC, card in either the N1, or the PC's card reader) was ~820KB/Sec
Writing the same data files to a Sandisk Class 2 16Gb card I achieved > 1.5MB/sec - i.e. approx twice as fast.
(PC is Acer Quad core 2.6Ghz jobbie with 8Gb RAM running Windows 7)
I found it really hard to get 4MB/sec out of the Kingston card - and only achieved it with 1 of the test options on CrystalMark. (write 1Gb sequential files)
When I tried this test with the 16Gb Sandisk class 2 card I got 10MB/sec. Clearly the SanDisk isn't a class 10 card - so I'm guessing the Crystal benchmark test isn't completely appropriate for SD card writers!.
I supplied Kingston with the packaging details / photos etc and they confirmed that it IS a real Kingston class 4 card. They agreed that performance should be better. LamndaTek clearly agreed too - after they received my return and tested it they gave me a full refund. (32Gb £83.66 (Inc VAT)). (Many thanks guys)
I guess the card was faulty.. but I might just be placing my trust in Sandisk now, as I've never had any problems with their cards.
I just thought that you all should know..
Graham

did you test it with a card adaptor or from the nexus one?
Also, if you're writing hundreds of small files vs one large file it makes a difference.

I think it was just a defective card.
Even the POS 32Gb cards floating around out there write at faster than 800kb/sec mb/sec.

SanDisk suck!
I will never buy any sandisk flash,sd card, micro again.. they have the worst CS i have ever delt with.. THey stand on their High Horse thinking their **** dont stink just because they said they only have a 1% defective rate.. which is crap if you ask me.. i went through some many defective flash drives used as keeping files on them and music to play in my scion xb.. So pretty much they told me i was mis using the device.. so i told them i would never buy from them..
so Kingston all the way now. they have the best CS i have ever delt with.. good day!

mynameisjon said:
did you test it with a card adaptor or from the nexus one?
Click to expand...
Click to collapse
I tested it with both options - the supplied adaptor - and also in the Nexus 1 - couldn't get it faster that I quoted, in any combination. Even tried a reformat - still no good.
Also, if you're writing hundreds of small files vs one large file it makes a difference.
Click to expand...
Click to collapse
It was a mixture of file sizes for the main copy, i.e. the contents of the 16Gb drive over to the 32Gb drive. About 14Gb were music files which come in at about 4Mb each.
As the other guys said above Kingston customer services were very responsive once they identified the card as genuine.. but LambdaTek were even more so.
I've still never had a Sandisk product give me an error though (I have 3 cards from them)
G.

I've used SanDisk for years without issue. Also been extremely happy with Lexar. Kingston, on the other hand, has been a complete letdown to me! A couple years ago, I bought a 4gb class 6 Kingston card for my digital camera. I didn't run any controlled benchmarks, but real-world use showed only about 2-3mb/sec transfer rates, which I thought was kind of slow. Also, as I was using a card reader instead of just plugging my camera in every time I needed to move pictures, the card was constantly being moved between devices. This proved fatal to the card, as the cheap plastic began to come apart. Never ever have I seen that happen to *any* SD card, even the cheap no-name ones! It started with the little tabs between each of the contacts, but didn't take long before the top and bottom of the card had begun to split. After a few months, the Kingston card was no good - all because of a disappointing casing. I wasn't rough with the card - I didn't treat this card any differently than others. In fact, I still have a 64mb SanDisk card from several years ago that's still going strong (great for sharing some jpgs, docs, etc.) So it might be worthwhile staying away from Kingston altogether...
Brands I've been happy with:
SanDisk
Lexar
Duracell
Transcend
Brands I've been disappointed with:
Kingston

so what is the deal with the N1 and its SD card speed?
i have a Transcend 8gb Class 6 card, i bought it for my G1 and recently got a N1.
on my G1 i would get an as expected 6 mb/sec or better copying files to/from it. in the N1 its never much more than 2mb/sec at most. this is apparently just when copying files via usb though
i just ran the app j bench mark 1.0.
when set to 10mb (2kb buffer) the default and lowest test setting i get
1.5mb sec write 2.5mb sec read
when set to 100mb (8km buffer) i get
6.16 mb/sec write
10.34 mb/sec read
so clearly internally the phone can and does handle the card at full speed but connected to PC's it does not.
and before anyone says it yeah i know just use a card reader to transfer large files.. whatever shouldn't need to do that imho
(megabytes not bits i am quoting here, i know the difference)

I have sandisk 16gb class 2 and under android 2.2 I gоt 1.5 mb/s and under android 2.1 I gоt 7-8 mb/s

gf_gollum said:
I'm sorry to report that I've returned the Kingston Class 4 32Gb microSD card for its failure to perform.
Performance writing to this Kingston card (from a desktop PC, card in either the N1, or the PC's card reader) was ~820KB/Sec
Writing the same data files to a Sandisk Class 2 16Gb card I achieved > 1.5MB/sec - i.e. approx twice as fast.
(PC is Acer Quad core 2.6Ghz jobbie with 8Gb RAM running Windows 7)
I found it really hard to get 4MB/sec out of the Kingston card - and only achieved it with 1 of the test options on CrystalMark. (write 1Gb sequential files)
When I tried this test with the 16Gb Sandisk class 2 card I got 10MB/sec. Clearly the SanDisk isn't a class 10 card - so I'm guessing the Crystal benchmark test isn't completely appropriate for SD card writers!.
I supplied Kingston with the packaging details / photos etc and they confirmed that it IS a real Kingston class 4 card. They agreed that performance should be better. LamndaTek clearly agreed too - after they received my return and tested it they gave me a full refund. (32Gb £83.66 (Inc VAT)). (Many thanks guys)
I guess the card was faulty.. but I might just be placing my trust in Sandisk now, as I've never had any problems with their cards.
I just thought that you all should know..
Graham
Click to expand...
Click to collapse
Had the same problem... RMA'd it with newegg and the replacement comes in tomorrow... I hold out hope.

Sandisk more me, no problem so far

My replacement Kingston class 4 holds out class 2 speeds on write of large files, less than that on write of small files. Blazingly slow on write, but faster on read than my class 6 8gb sandisk...
All in all... I can live with it for now...

The article below is an interesting read regarding Kingston and the sdcard market in general.
http://www.bunniestudios.com/blog/?p=918

[Q] Which sd card is better?

So Ive been using the 16gb Class 2 sd card that came with my HD2 for WP7 and I havent really had any problems with it. Occasionally it reboots for no reason, but aside from that, its perfect. However, my friend just gave me his 4gb Class 4 card. Should I keep using the 16gb or reset my phone with the faster 4gb?

simple test, all sd cards work differently
my Nokia 4GB Class 6 is better than may Sandisk 16GB Class 2
Xbox Live Installation: ( only the installation without download )
Nokia 4GB Class 6: 1:23 minutes
Sandisk 16GB Class 2: 9:41 minutes

peace warhead said:
So Ive been using the 16gb Class 2 sd card that came with my HD2 for WP7 and I havent really had any problems with it. Occasionally it reboots for no reason, but aside from that, its perfect. However, my friend just gave me his 4gb Class 4 card. Should I keep using the 16gb or reset my phone with the faster 4gb?
Click to expand...
Click to collapse
Class 2 cards usually work better for wp7. Actually class means nothing when it comes to wp7... you want good random access speed for wp7 to run smooth. Many times, the tricks that manufacturers do to their cards to get higher sequential write speeds will actually reduce the random access speed. They don't keep the random access speed consistent on any of their cards as that speed isn't rated, so even cards of the same brand and class can differ greatly from batch to batch. A card made one day may run wp7 well while the same card made a month later may not. So far it seems class 2 sandisk are the most consistent in keeping good random access speed, so if you are going for a card for wp7, go for class 2 sandisk with model numbers ending in A11M. If you already have a card that works well, no reason to switch unless you want to change the size, because there's no way to guarantee a card will work well until it's tested.

[Q] tmobile HD2 problem: Microsd 32Gb class 10 copy speed less than 4MB/sec

I got a 32Gb MicroSDHC class-10 memorette card.
I verified the speed with a card reader + h2testw that write speed is : 14.7MByte/sec
read speed: 17.5MByte/sec
But when I used the class10 card in tmobile HD2, I am shocked.
When I copy a 720MB movie the write speed is about 4MByte/sec.
h2testw program when used on hd2 connected to PC, showed write speed as 4.8 MByte/sec only.
It needs to be noted the same card when tested with h2testw and a card reader gave 14MByte/sec but gives less than 4.5MB/sec on HD2.
How to fix this problem of HD2 microsd card speed!
Looks like HD2 usb controller has some problem.
the card is indeed class-10.
Please let me know a solution to this problem on HD2.

downbc1 said:
I got a 32Gb MicroSDHC class-10 memorette card.
I verified the speed with a card reader + h2testw that write speed is : 14.7MByte/sec
read speed: 17.5MByte/sec
But when I used the class10 card in tmobile HD2, I am shocked.
When I copy a 720MB movie the write speed is about 4MByte/sec.
h2testw program when used on hd2 connected to PC, showed write speed as 4.8 MByte/sec only.
It needs to be noted the same card when tested with h2testw and a card reader gave 14MByte/sec but gives less than 4.5MB/sec on HD2.
How to fix this problem of HD2 microsd card speed!
Looks like HD2 usb controller has some problem.
the card is indeed class-10.
Please let me know a solution to this problem on HD2.
Click to expand...
Click to collapse
The HD2 doesn't read or write to sd cards at that high of speed... that's why it's pointless using class 6 or 10 cards in a HD2. I think most phones are like that. Class 6 and 10 cards are mainly used for digital cameras, where having high sequential write speeds matters.

zarathustrax said:
The HD2 doesn't read or write to sd cards at that high of speed... that's why it's pointless using class 6 or 10 cards in a HD2. I think most phones are like that. Class 6 and 10 cards are mainly used for digital cameras, where having high sequential write speeds matters.
Click to expand...
Click to collapse
I have earlier used a nokia 5800 xpressmusic phone with a class 6 16GB card.
The data transfer speeds were higher than HD2.
Generalizing from a single instance (HD2 scenario) may not be correct.

I'm going to go with that the HD2 does not transfer faster than 5.3 MB/sec between the PC and the phone regardless of what the internal transfer rate between the phone and card is.
Using a class 6 card myself, i have noticed that the phone is much more responsive than it was with the class 2 card in there and movies play without stuttering from the class 6 card and applications launch quicker.
my nokia n81 8gb did 8MB/sec from internal 8GB and so did my KM900. The KM900 did 6.2MB from the same classs 6 card

I was under the impression the HD2 maxed at 16 gig. Maybe that's the problem?

Like zarathustrax said, the HD2 isn't capable of read/write any higher than a class 4 card. I think somewhere on the EVO forum there's a fix to unlock the read/write capability for a higher speed but I dunno if anyone here has tried the fix, or if it even works for the HD2 at all.

anhyeuemmaimai said:
I'm going to go with that the HD2 does not transfer faster than 5.3 MB/sec between the PC and the phone regardless of what the internal transfer rate between the phone and card is.
Click to expand...
Click to collapse
This is not true. I've copied large files at over 10MB/s directly to the phone. I can't vouch for every hd2 though as it's quite possible they have different hardware. Also the speed drops dramatically if you're copying many smaller files.

I am thinking to buy memorette 32 gb microsd class 10 for my HD2.
As far as I have understood:
1) No matther what I cannot use it fully Class 10 speed when connected to HD2
2) When I connect it to my PC with card reader I can fully use class 10 speed.
I have sandial 8 gb class 2. When I connect it to my pc with card reader and transfering large amount of data (150+ MB), it cease to operate. I have to reconnect it. Then I shuld transfer in less amount of data or reduce copy speed (such as UltraCopy) . I think that is a safety issue for preventing disk from get burned. My question is, will I possibly have some issues with memorette or some other class 10 cards?
Also would it not better using class 10 card in HD2 for using on SD installed Operating System instead of class 6 or 4?
I would appriciate if someone return about memorette. I have never heard about that trademark. I am planning to bid on ebay today.
Sent from my HTC HD2 using XDA App

lude219 said:
Like zarathustrax said, the HD2 isn't capable of read/write any higher than a class 4 card. I think somewhere on the EVO forum there's a fix to unlock the read/write capability for a higher speed but I dunno if anyone here has tried the fix, or if it even works for the HD2 at all.
Click to expand...
Click to collapse
fix to unlock the read/write capability for a higher speed ????? Really ... i have buy a micro sd 16GB class 10 ........

morfil said:
I am thinking to buy memorette 32 gb microsd class 10 for my HD2.
As far as I have understood:
1) No matther what I cannot use it fully Class 10 speed when connected to HD2
2) When I connect it to my PC with card reader I can fully use class 10 speed.
I have sandial 8 gb class 2. When I connect it to my pc with card reader and transfering large amount of data (150+ MB), it cease to operate. I have to reconnect it. Then I shuld transfer in less amount of data or reduce copy speed (such as UltraCopy) . I think that is a safety issue for preventing disk from get burned. My question is, will I possibly have some issues with memorette or some other class 10 cards?
Also would it not better using class 10 card in HD2 for using on SD installed Operating System instead of class 6 or 4?
I would appriciate if someone return about memorette. I have never heard about that trademark. I am planning to bid on ebay today.
Sent from my HTC HD2 using XDA App
Click to expand...
Click to collapse
A good quality class 2 or 4 sd card is usually better for running an operating system off of, as lower class cards tend to have faster random access speed and better random read/write speeds. Class 6 and 10 sd cards are designed to have a higher sequential write speed, but to achieve these higher speeds, the card initializes the part of the card that's about to be used. The initialization takes some extra time to get started, but boosts the sequential write/read speed so it's great for digital cameras or writing files sequentially.
But when it comes to using the card to run an OS off of, like android or wp7, or using the card to run apps off of, you are going to be reading and writing many small bits of data from different parts of the card. When it comes to this, you need a card that has a good random access speed and random read/write speeds. A high class card that is tweaked to have high sequential read/write speeds ends up being slower because it keeps initializing each part of the card before accessing it, while the lower class 2 or 4 card that doesn't do the initialization is a lot quicker accessing many small parts of the card because it doesn't have that extra step... but they don't get the speed boosts with sequential read/write.
Many people just assume that a higher class card is always going to be better, but this isn't true at all. It all depends on what you are using the card for. Higher class 6 or 10 cards are perfect for digital cameras, recording video, or transferring large files, etc... if you are going to be doing sequential reading or writing, higher class is better.
But for running apps off of, or running an OS off of, or using it as internal memory for an OS like wp7, or anything that will be accessing many parts of the card quickly or reading many small bits of data, etc., you want a card with a good random access speed and random read/write speeds, and that is something that is not rated on cards... but generally lower class cards are better than higher class cards... especially if you get a good quality brand, like sandisk. Sandisk class 2 and 4 are very good cards for random access speeds.
I hope some of you find this info useful and stop assuming a higher class card means better for all situations.

buzz killington said:
This is not true. I've copied large files at over 10MB/s directly to the phone. I can't vouch for every hd2 though as it's quite possible they have different hardware. Also the speed drops dramatically if you're copying many smaller files.
Click to expand...
Click to collapse
You must be special then. In my tests I had no difference in a class 2 and class 6.

morfil said:
I am thinking to buy memorette 32 gb microsd class 10 for my HD2.
As far as I have understood:
1) No matther what I cannot use it fully Class 10 speed when connected to HD2
2) When I connect it to my PC with card reader I can fully use class 10 speed.
I have sandial 8 gb class 2. When I connect it to my pc with card reader and transfering large amount of data (150+ MB), it cease to operate. I have to reconnect it. Then I shuld transfer in less amount of data or reduce copy speed (such as UltraCopy) . I think that is a safety issue for preventing disk from get burned. My question is, will I possibly have some issues with memorette or some other class 10 cards?
Also would it not better using class 10 card in HD2 for using on SD installed Operating System instead of class 6 or 4?
I would appriciate if someone return about memorette. I have never heard about that trademark. I am planning to bid on ebay today.
Sent from my HTC HD2 using XDA App
Click to expand...
Click to collapse
I am using memorette class 10 32GB microsd currently.
Its affordable and is fully working. I have tested to full capacity read/write using h2testw as I wrote in an earlier post.
Just check the seller's feedback and the description though.

I use TEAM micro sd class 10 on my hero,but after a month my sd card write speed is only 2MB/s.
At the first time,it reach 11MB/s when i tested it with h2testw and sd speed test on my handset.
I only use 640MB for app2sd (ext2) without swap cache.
Could someone explain to me what was happen to my sd card?
Sorry for my bad English

Micro SD Card Class Rating

How much does the class rating of an SD card make a difference in a phone?
New Egg has a great deal on a 16GB Class 4 card.
I have a class 4 card now, but I've never used a 6 or 10. So I don't know if there's a whole world of performance I'm missing out on.
I run Cyanogen so I do have a considerable amount of APP2SD action going on. But I don't otherwise write to the SD card a considerable amount. Don't take a lot of videos....don't transfer 4 or 5 GB worth of music everyday. Nothing like that.

Visit Wikipedia or Google for the transfer rates and think about how much I/O you will be doing. The more stuff apps and data you store on your card the more important the performace and compare that to what experience you have.
Being used to sticking a stick in a USB 1.1 slot and groaning at old computers, so I tend to divide by 2 when judging such things. E.g. if it's 480m/b, I make the expectation off reality being closer to 240m/b. Can't complain about MicroSD's much since my current handset has a freebie 2GB >_<. I assume it's class 4 but it is fine for me, and most of my stuff is on it.
Sent from my Transformer TF101 using Tapatalk

Take one thing into consideration: class of the SD card means nothing, if the device's own transfer (specifically, write) rate is too slow to utilize it.

Jack_R1 said:
Take one thing into consideration: class of the SD card means nothing, if the device's own transfer (specifically, write) rate is too slow to utilize it.
Click to expand...
Click to collapse
Well that's a good point.
I have no idea what the write speed of a MT4G is. But I've had a Class 4 card since I bought the phone and it seems to work nicely. I've never said "Man I can't believe it's taking this long to save this file!"
So I went for the $17 special on New Egg for a 16GB Kingston card.
Search micro SD card 16gb on New Egg. It's the cheapest one. Brand name. Free shipping. Can't go wrong there.

No point in getting a class 10 unless you transfer via this usb adapters.. I think the mytouch stops at like class 8. Not worth it unless on sale. You can live with a couple seconds of wait time
Sent from my HTC_Amaze_4G using XDA App

Jack_R1 said:
Take one thing into consideration: class of the SD card means nothing, if the device's own transfer (specifically, write) rate is too slow to utilize it.
Click to expand...
Click to collapse
I agree, I wouldn't go any higher than a class 4 or 6 for a phone. I have a ADATA 16gb class 6 and have never had any problems with transfer/read/write speeds
Sent from my HTC Glacier using xda premium

I have a Class 10 card, but only because I transfer files to and from my computer on a semi-regular basis. I used an 8GB microSDHC Class 4 card in my previous phone and one time I found myself needing to transfer a lot of data off of a computer. All I had left on hand was that Class 4 card with its SD adapter and it was horribly slow in my SanDisk MicroMate adapter that I typically use in conjunction with a 4GB SanDisk Extreme III SDHC card as a flash drive.
I agree that you're not going to get much more out of the phone itself beyond Class 6.