Dear readers,
I'm searching a for a new SD card for my HD2 for a while now and wanted to buy a 32gb class 10 microsd card from samsung.
But then i saw a new cards with new classes called "UHS".
I also saw one of them having the class 6 and the UHS class.
I have a few question regarding this:
1. Does this UHS class work on the HD2?
2. Is it possible for a card to have a normal class and a UHS class?
3. if not, are UHS 1 cards as fast as class 10 cards on devices that do not support UHS?
4. How can UHS 1 be cheaper then class 10?
adata 32gb micrsosd UHS 1: cant post url...
the same card for 22 euro's: cant post url...
samsung 32gb microsd class 10 for 26 euro's: cant post url...
I hope this topic will answer the the questions i think other people have too.
kind regards,
4rjan
Can't answer for sure if they are 100% compatible with HD2 hardware(there is certain hardware requirement for UHS), but in theory any speed after class 8/10 is pointless. Class 10 is close to HD2 hardware bandwith limit. You won't benefit that.
Nobody??
I was also looking for a 32GB class 10 card and found the UHS-i type, but in the reviews i saw said about compatibility issues in non compatible devices or transfer speeds relatively low in devices without UHS-i compatibility.
To avoid problems i purchased one Samsung Class 10 card, works perfectly in my HD2 and don't have to worry.
That is exactly what i thought, that the uhs-i has a lack of performance on not supported uhs-i devices and that they are not completely backwards compatible to normal class 10 speed.
Do you maybe have a URL of those complaints?
hardan said:
I was also looking for a 32GB class 10 card and found the UHS-i type, but in the reviews i saw said about compatibility issues in non compatible devices or transfer speeds relatively low in devices without UHS-i compatibility.
To avoid problems i purchased one Samsung Class 10 card, works perfectly in my HD2 and don't have to worry.
Click to expand...
Click to collapse
That would be expected for transferring relatively small files and using windows formatting as the random read/write speed (most frequently used) will be slower with a higher class, whereas the sequential read/write speed will increase. This may beneficial for users with WP7 but if you use it anywhere else it will seem much slower.
Sent from my T9193 using xda
But do UHS class 1 cards run ass class 10 cards when they are used with non supported UHS devices? If it is true what you guys are saying then its not.
I can't find anything about it on the English Wikipedia, but on the dutch Wikipedia it says it runs like class 10 on non supported devices:
http://nl.wikipedia.org/wiki/SD-kaart
UHS: MB (Megabyte) Mb (Megabit)
UHS Class 1 10 MB/s (min) 80 Mb/s (min)
UHS-I 104 MB/s (max) 832 Mb/s (max)
UHS Class 2 105 MB/s (min) 840 Mb/s (min)
UHS-II 300 MB/s (max) 2400 Mb/s (max)
Home » Frequently Asked Questions » Memory Card
WHAT IS UHS-1 ?
"UHS-1" or more accurately "UHS-I" stands for "Ultra High Speed" - 1 and is a speed class for SDHC and SXDC memory cards.
UHS-I is the fastest category of card available today with a bus interface speed of up to 104 MB/s.
An SDHC UHS-I card will work in any SDHC compatible device at lower speeds, but to take advantage of the UHS-I speed, a UHS-I compatible device is essential.
omidz said:
An SDHC UHS-I card will work in any SDHC compatible device at lower speeds, but to take advantage of the UHS-I speed, a UHS-I compatible device is essential.
Click to expand...
Click to collapse
the question is what are those "lower" speeds?
4rjan said:
the question is what are those "lower" speeds?
Click to expand...
Click to collapse
The speeds would be the Class 6 or Class 10 speeds, depending on what's listed on the card. Of course, even that can be bottlenecked by your device's cache.
UHS-I doesn't work nice!
I try to use a SanDisk 16GB class10 Ultra MicroSd HC-I but as I found out it doesn't feet with my HD2 EU..... ...Although it works very smooth and fast after some hour my phone just freezes....only the light of the hardbuttons works...screen turns black...I take off the battery...and all this sadness comes to my face...
So I got back to my Transcend 16GB class10 and everything works almost fine (a little bit slow sometimes, so I use sd card boost and swapper2).
You can see by yourself ...the mmc driver has not included UHS mode...
UHS vs CLASS
The UHS means it has content transfer speed of minimum 30mbps to maximum of 104mbpswhen you transfer the content from MicroSD to System(PC)....but the data write speed on the MicroSD depends on the CLASS mentioned on it i.e., CLASS 10 has MAX write speed of 10MB/S......(Note: all this speed transfer test will use top speculated system configurations so it may vary on our PC's).
Hello,
Just to echo what a few people have said elsewhere and clarify something. Using an SDcard with a UHS classification may well cause your HD2 to hang, black screen, freeze, crash .... especially when using certain ROMs. Some seem more resilient than others, but the NativeSD ROMs in particular rely heavily on accessing the SDcard. The only way to reset after a blackscreen is to remove battery and reboot.
The HD2 was never designed to work with these cards and they require specific voltages from the phone hardware in order to run correctly. The HD2 does not have such hardware. I used a Sandisc 16GB Class-10 UHS-1 card and my phone would hang/crash 7-10 times each day. After replacing it with a Class-10 Kingston card with no UHS classification, the phone runs fine. Nothing else was changed except the SDcard. The exact same installation was used by cloning the SDcard partitions. Consequently the phone runs fine now.
Just thought I'd post up in case it helps others.
Would appreciate if someone could mirror this post for me (I have less than 10 posts on XDA and don't want to spam the forum just to get them) on this thread for [ROM][4.1.2][720p] NexusHD2-JellyBean-CM10 V1.5 [NativeSD] because a few people were complaining of bugs and it's nothing to do with the ROM itself, more the memory cards they are using.
doctorasgr said:
I try to use a SanDisk 16GB class10 Ultra MicroSd HC-I but as I found out it doesn't feet with my HD2 EU..... ...Although it works very smooth and fast after some hour my phone just freezes....only the light of the hardbuttons works...screen turns black...I take off the battery...and all this sadness comes to my face...
So I got back to my Transcend 16GB class10 and everything works almost fine (a little bit slow sometimes, so I use sd card boost and swapper2).
You can see by yourself ...the mmc driver has not included UHS mode...
Click to expand...
Click to collapse
Use 32GB Sandisk class10 Ultra UHS HC-I without a single issue. Did want the mobile Ultra class 6 to be safe but sent me class10 UHS but worked out fine ...
Mister B said:
Use 32GB Sandisk class10 Ultra UHS HC-I without a single issue. Did want the mobile Ultra class 6 to be safe but sent me class10 UHS but worked out fine ...
Click to expand...
Click to collapse
:thumbup:
Enviado desde mi GT-I9300 usando Tapatalk 4 Beta
Very strange,i using a Sony 8GB UHS-1 and it works fine with all roms (dataonext,nativesd).I'm thinking to buying a Sony 16GB UHS-1
I am using SanDisk ultra 16Gb UHS-1 card without any issue for some time now with many different ROMs. I would rather bet that not original (Kingston, Sony, no names) that looks like original cause that.
guys what do you think about this card http://youtu.be/PuHfmuJ8pf0.... I am about to buy a new 32gb card for my new phone.
please give suggestions....
Related
Hello Every Body,
Can any body please confirm if the class 10 32 gb memory cards such as Kingston or A-Data are compatible with HTC HD7.
I read here before in XDA that only the class 2 cards from Scandisk are only the one that are compatible with the windows phone 7 devises.
But in this thread http://forum.xda-developers.com/showthread.php?p=10354934
dorianmuthig says that class 4 cards are compatible also.
So my Questions are:
1- Are Kingston or A-Data or other brands are compatible with the HD7 (because I already have 32 gb class 10 A-Data memory card)?
2- Are class 4 or above classes are compatible also?
Thanks in advance and I appreciate if any body can clear these inquiries for all to be benefited.
There is no such thing as a class 10. and as i have read at multiple places only class 2 sandisk cards have been confirmed working. everything else doesnt work this means class4 etc...
nuclear said:
There is no such thing as a class 10. and as i have read at multiple places only class 2 sandisk cards have been confirmed working. everything else doesnt work this means class4 etc...
Click to expand...
Click to collapse
Thanks nuclear for replay,
for your information there is a class 10 32 gb memory card
I hope that some body who tries higher classes than class 2 tells us his experiment
Apparently there is class 10 (16 and 32gb) cards available. http://www.google.com/search?sourceid=chrome&ie=UTF-8&q=class+10+32+gb+microsd But, from what has been discussed class 2 are the only ones that have been confirmed to work properly (not decreasing boot times and app launching times). So, I would be cautioned to buy one until there is more definitive information as they have to be pretty expensive.
kwill said:
Apparently there is class 10 (16 and 32gb) cards available. http://www.google.com/search?sourceid=chrome&ie=UTF-8&q=class+10+32+gb+microsd But, from what has been discussed class 2 and 4 are the only ones that have been confirmed to work properly (not decreasing boot times and app launching times). So, I would be cautioned to buy one until there is more definitive information as they have to be pretty expensive.
Click to expand...
Click to collapse
Where did you read about the class 4 card?
nuclear said:
Where did you read about the class 4 card?
Click to expand...
Click to collapse
Oops, my bad. Mis-stated that one. Class 2 is all that's confirmed. For some reason i was thinking the tutorial to change it to 32 gb was using a class 4. Slap me
It seems that we should wait for some time to be sure
And if any body try other classes higher than class 2, please inform us withj the results
It may work, however since Kingston and A-Data use Sandisk or Samsung manufactured cards with a secure digital storage controller optimized for fast sequential read and write, small file access may actually be slower than in a comparable Class 2 card. Those fast cards are made for video recording and high resolution photography which isn't what Windows Phone 7 OS needs. You need to look at 4K random read, 512K random read/write and sequential write.
Get either a Sandisk SDSDQM-032G-B35 (definitely works) or SDSDQM-032G-J35A (current manufacturing cycle, promises faster speeds and lower power consumption, still rare)
kingston class 4 = does NOT work.
sandisk class 2 = works (same speeds as the kingston though!)
thats as far as i tested.
pencilcase said:
kingston class 4 = does NOT work.
sandisk class 2 = works (same speeds as the kingston though!)
thats as far as i tested.
Click to expand...
Click to collapse
Thanks for the advice,
But what about scandisk class 4 or higher are they workable
ihabsad said:
Thanks for the advice,
But what about scandisk class 4 or higher are they workable
Click to expand...
Click to collapse
SanDisk class 4 has just been released and is available on Amazon for $100. I am getting a class 2 which is tested and confirmed working. The class 4 if it works should be much faster.
Sandisk SDSDQM-032G-B35 was not working properly on my HD7. Slow, freezing, crashing, and sometimes not detected card. All kinds of bad behavior. The original 16 GB card was sent back into the phone, now every thing works OK.
I'm going to buy a 16GB microsd card from sandisk. I've been finding on Amazon and found these two products:
Sandisk 16GB Mobile Ultra MicroSD Card : £36.00
SanDisk 16GB microSDHC Memory Card : £15.99
I've also noticed they're all class 2 (can't find a class 4 or class 6 sandisk). So what is the difference between them? I'm using the card for Windows Phone 7, so which one should I buy?
http://en.wikipedia.org/wiki/SD_Memory_Card#SDHC_cards_with_greater_than_32.C2.A0GB_capacity
as I understand it the only advantage of SDHC is an increased card storage. And im not sure if an SDHC card works in the HD2.
uxu said:
http://en.wikipedia.org/wiki/SD_Memory_Card#SDHC_cards_with_greater_than_32.C2.A0GB_capacity
as I understand it the only advantage of SDHC is an increased card storage. And im not sure if an SDHC card works in the HD2.
Click to expand...
Click to collapse
Both of them should be SDHC (>2GB). I'm asking about the Ultra thing.
Zell Dinch said:
Both of them should be SDHC (>2GB). I'm asking about the Ultra thing.
Click to expand...
Click to collapse
Sorry, got it wrong
They're the same thing. One has an adapter however
Ultra means it has higher transfer speeds.
There's also Ultra and Extreme in the regular SDs.
Ultra=15 mb/s
Extreme=30 mb/s
So it's all about speed.
@apallohadas: they have different model number, one is SDSDQY-016G-E11M and one is SDSDQ-016G-FFP. And I suspect that just a card reader will make that difference in price.
@joooe: but they're both class 2?
I've tried several different class cards in my HD2, and regardless of advertised 'class' r/w speeds only changed noticeably if I took it out of my phone and used a card reader or adapter like shown in the "ultra" listing you have.
apallohadas said:
I've tried several different class cards in my HD2, and regardless of advertised 'class' r/w speeds only changed noticeably if I took it out of my phone and used a card reader or adapter like shown in the "ultra" listing you have.
Click to expand...
Click to collapse
Hello apallohadas
can you confirm or any one without any doubt that there is no difference in R/W speed between class 2 or class 4 or class 6 inside HD2 with Windows 6.5 or Android
thanks
secoseco said:
Hello apallohadas
can you confirm or any one without any doubt that there is no difference in R/W speed between class 2 or class 4 or class 6 inside HD2 with Windows 6.5 or Android
thanks
Click to expand...
Click to collapse
I don't have Winmo installed on my phone anymore, so I can't rerun that test and I didn't keep the numbers last time that I did it.
But if you'd like to try testing cards yourself, I used a program called H2test and a card adapter. My Class 2 Sandisk 32GB card gave numbers comparable to a class 6 Transcend 16GB.
Inside of the HD2 however, while on Android the tests take too long (setting read/write file sizes of 1GB+.) I've read in several places that the hardware limits performance as though they were all class 2 cards.
There are reviews where a class 4 card is superior to a class 6 card.
Sandisk cards are just great.
In the sandisk website there is no info about the class of both cards. Don't believe they have the same class.
apallohadas said:
I I've read in several places that the hardware limits performance as though they were all class 2 cards.
Click to expand...
Click to collapse
thank you apallohadas for replay
I think so, hardware limitation to Class 2 with HD2 although I read in several places that there is more performance with Class 6 or 10 card in Android especially SD Android
I have Sandisk 16G class 2 and want to upgrade to 32G and I don't want to wast my money in useless class 6 or 10 with my EU HD2,
any one use Sandisk class2 then upgrade to class4 or 6 with EU HD2 and get faster performance in read and write inside HD2 not as disk drive ??
thanks
Hello
I got my Legend about 2 months ago, and I have a big problem with storage space...
What is the biggest sized SD card the Legend can use?
What is the type of SD card (micro, mini, etc...)
What is SD card class?
Thank you very much
microSD compliant with SD2.0 Standard (aka microSDHC)
The biggest size available currently is 32GB.
I don't know if even more is possible with microSDHC or if bigger cards will only be possible with SD3.0 (aka SDXC) but that question is not relevant as you can't buy any greater then 32GB yet.
The Class of the SDCard is a measurement for guaranteed minimum speed in random read/write.
The Class does not provide any information about real-world speed or max speed.
For your mobile phone the class is a pretty useless criterion as you don't need any guaranteed minimum speeds but good overall speeds ESPECIALLY sequential.
The guaranteed minimum speed is important for HD Video Cameras for example where you write data all the time at a given speed (resolution).
thanks.
but I DO need class with high speed because I want to use Data2Ext...
Don't pick uSD card based on class !! class tels you MB/s for sequential write only... you need a card that is overall fast, I had 16GB class 10 Kingston and data2ext was just horrible!
Now I'm with class 4 Sandisk mobile ultra and it is in fact faster in every test I ran...
So read reviews before you buy
ye but that is exactly why im asking...
well then, I recommend sandisk mobile ultra as I have it and it is OK, there are probably faster cards...just see the small files read / write speeds in reviews those are of greatest importance
i purchased a kingston 8GB class 4 which crapped out. android kept reported sdcard unexpectedly removed. tried all sorts (formatting in windows, android, quick, long, etc).
RMA replacement did exactly the same, so i'm guessing kingston class 4's are best avoided.
If I recall correctly I have a 16GB microSDHC Class 4 card. After applying data2ext with this card, my Quadrant scores hit around 1500, which is crazy.
This is where I found my card: http://www.amazon.co.uk/SanDisk-16G...P06K/ref=sr_1_1?ie=UTF8&qid=1298984123&sr=8-1
I personally recommend this card.
witch is better class 4 or class 6?
r69001 said:
Hello
I got my Legend about 2 months ago, and I have a big problem with storage space...
What is the biggest sized SD card the Legend can use?
What is the type of SD card (micro, mini, etc...)
What is SD card class?
Thank you very much
Click to expand...
Click to collapse
Did you by any chance go to HTC's website to read about the phone? It has the full specs listed..
Sent from my Legend using XDA App
dangal said:
witch is better class 4 or class 6?
Click to expand...
Click to collapse
class 6 is better , but class 10 is even better
I've got a Sandisk Ultra Mobile 16gb SDHC which works fine in the Legend. Make sure you format it with the phone to stop it being dismounted, well known issue and the fix
I bought 8G (Class 10) memory card. but i don't think my phone(x8) support it?
in all of tests, My phone shows has class 4. Is it correct?
did you buy the card from Ebay or is it from a reputable source? Eg are you sure the card is a genuine class 10?
Swyped from HTC Desire S using XDA Premium
I don't know, how can i understand it is original?
insert your card into cardreader and record big file, and check record speed.
Have a look at the sdcard.
The most of the sdcards have a little number in a circle on it, and that´s the class of the sdcard.
So, if you can find a "10" in a circle on your card, it´s class ten.
if you have another number in a circle on it, then it´s not class 10
It may be a hardware problem, but testing the speed on a pc would be taking you out from the doubt.
I'm using a class 10 8gb Kingston microSD. No problem at all.
However, I experienced heavy writing problems with class 4 8gb Kingston. This was the reason why I had to resell this card, only to check with my own eyes the problem was on the x8 and not in the class 4 microSD.
I tested my 8G-Class 10 microSD with Ram Reader,
File: 699 Mb
write: 90 s ----- 7.8 Mb/s
Read: 65 s ----- 10.75 Mb/s
File: 398 Mb
write: 50 s ---- 8 Mb/s
Read: 20 s ---- 19.9 Mb/s
How do you think a bout my class of microSD?
Its class 8
Sent from my X8 using XDA Premium App
kingstone products have a lot of compatibility problems, i know they're popular but they suck.
I'm using an SDHC A-Data 8 Gb class 10 and works great.
cdanisor said:
kingstone products have a lot of compatibility problems, i know they're popular but they suck.
I'm using an SDHC A-Data 8 Gb class 10 and works great.
Click to expand...
Click to collapse
and become a faster relno from this phone?
XperianPro said:
Its class 8
Sent from my X8 using XDA Premium App
Click to expand...
Click to collapse
Those results mean nothing, there are lots of things that can influenciate speed. Also, the cards' speed is tested on factory with a special machine, not a computer, so real world speeds are always a bit slower. If the card was a fake i think it would be getting far worst performance.
Test it on a desktop pc (rear ports) using a decent card reader.
Sent from my E15i using XDA App
I have a kingmax class 10 8GB.
In pc, i can reach around 14.x mb/s.
In phone, fastest is 8mb/s, but in average 6mb/s+.
molimo said:
I bought 8G (Class 10) memory card. but i don't think my phone(x8) support it?
in all of tests, My phone shows has class 4. Is it correct?
Click to expand...
Click to collapse
Friends
At last, I tested my microSD (class 10) in Galaxy S I9003 with "SD Tools v2.1" & "SD Card speed test v1.9" applications, They show that the class of my microSD is 10, then tested again in x8 and show class4 or class6.
conclusion: Our x8 can't support class 10. it support class up to 6.
It's true that the sd card interface of the X8 can have a limit below class 10, but remember that there are always factors that can limit the speed.. Partition type, allocation unit size, ROM, kernel.. But yeah, i won't be surprised if it had a limit of roughly 6MB/s..and it's not that bad
Class 10 is very smooth for ungaze...
I test my 16GB V-Gen class 10 memory card with sd tools and the result:
read speed : 14,4 mbps
write speed : 8,2 mbps
i use 32k allocation unit size when formatting through computer,,
i have 8GB AData class 10 and work fast and smooth
Read 20 mb/s
Write 12 mb/s and some time more
can someone confirm if X8/W8 can benefit class 10? cause I have here class 6 offered by a friend for a very cheap price cause it is second hand
amnher said:
can someone confirm if X8/W8 can benefit class 10? cause I have here class 6 offered by a friend for a very cheap price cause it is second hand
Click to expand...
Click to collapse
i can confirm, because i use it.. i have AData 8GB class 10 card.
Cacobronx said:
i can confirm, because i use it.. i have AData 8GB class 10 card.
Click to expand...
Click to collapse
but compared to class 6? is it really big?
I was reading this forum post which claimed that a class 4 card is actually faster than a class 10 card for Cyanogenmod on the microsd card. Is that true? I currently have the 64GB san disk class 10 card (the red/grey one) as my card. It does tend to lag a bit if i'm swiping from one home screen to another. Would a class 4 card give me smoother performance?
http://forums.anandtech.com/showpost.php?p=34988392&postcount=30
If it's a Sandisk class 10, it's probably fine.
What the problem is that Sandisk's class 4 cards often perform better than the class 10 cards from other manufactures like Patriot. I have a class 4 Sandisk and a class 10 Patriot and the Sandisk is superior at 4k performance. But the class 10 Sandisk is probably fine (assuming it's a real Sandisk and not a counterfeit).
Ravynmagi said:
If it's a Sandisk class 10, it's probably fine.
What the problem is that Sandisk's class 4 cards often perform better than the class 10 cards from other manufactures like Patriot. I have a class 4 Sandisk and a class 10 Patriot and the Sandisk is superior at 4k performance. But the class 10 Sandisk is probably fine (assuming it's a real Sandisk and not a counterfeit).
Click to expand...
Click to collapse
Thanks, oh you're Ravynmagi from that same thread eh? Hahaha
Class 10 cards are best for long r/w for large files or a video camera. Most of what the tablet or phones do are shorter r/w and a class 6 or 4 will do fine or even be superior. This is particularly true for cards that are used for part of the operating system. This info was gleaned from experience with Android, NativeSD roms. If you search nativesd + hd2 there much info.
Many of the class 10 labeled cards are mislabeled anyway. A name brand like Sandisk will be more quality tested and properly labeled.
Hello guys, this is my first post here. Instead of starting a new thread, I thought it'll be appropriate to post in a thread about sd cards. I'm planning to buy microsd cards for my new Nook HD+, which is on the way. Does UHS-1 micreosd cards work with Nook HD+? I want to dual boot with cynagen mod on sd card. Which class'll be the best for running android from the sdcard? Also I want to make a back up of my Nook HD+ stock version, what size card is enough for that?
The card that I have in mind is a Strontium 16GB UHS-1 MicroSDHC Card. In its product description it says "Compatible with SDHC and SDXC host devices; not compatible with standard SD-enabled devices/readers" and "Compliant with the new UHS-I specification for ultra-high speed interfaces for SD specifications. Can only be used in UHS-I mode in UHS-I compatible devices." (I can't post link since it's my first post)
I got confused after reading that highest class won't give optimal performance. I hope some one here will help me in this. Thank you.
mashac said:
Hello guys, this is my first post here. Instead of starting a new thread, I thought it'll be appropriate to post in a thread about sd cards. I'm planning to buy microsd cards for my new Nook HD+, which is on the way. Does UHS-1 micreosd cards work with Nook HD+? I want to dual boot with cynagen mod on sd card. Which class'll be the best for running android from the sdcard? Also I want to make a back up of my Nook HD+ stock version, what size card is enough for that?
The card that I have in mind is a Strontium 16GB UHS-1 MicroSDHC Card. In its product description it says "Compatible with SDHC and SDXC host devices; not compatible with standard SD-enabled devices/readers" and "Compliant with the new UHS-I specification for ultra-high speed interfaces for SD specifications. Can only be used in UHS-I mode in UHS-I compatible devices." (I can't post link since it's my first post)
I got confused after reading that highest class won't give optimal performance. I hope some one here will help me in this. Thank you.
Click to expand...
Click to collapse
SanDisk class 4 are the best to use for everything on the HD/HD+. The device does not work reliably with faster cards.
You need about 1.5GB to do a stock backup, so a 2GB is enough.
Sent from my Nook HD+ running CM10.1 on emmc.
leapinlar said:
SanDisk class 4 are the best to use for everything on the HD/HD+. The device does not work reliably with faster cards.
You need about 1.5GB to do a stock backup, so a 2GB is enough.
Click to expand...
Click to collapse
Thanks leapinlar for that quick reply. So, a 16 or 32GB class 4 sandisk card for the dual boot and another 2GB card for the stock backup is all I need. Thanks again.
The "class' rating is only a measure of large sequential write performance, as in using it for an HD video camera. The class rating has no bearing at all on random access speeds or small reads and writes. Many sandisk class 4's have faster small random read/write performance than many class 10 cards, but its worthwhile to look at benchmarks for a card you're looking at or a list of top cards for tablet/phone usage that keys on small random read/write performance for optimal performance.
In fact, the sd card market is loaded with class 10 cards that stink at pretty much every other measure than large sequential writes.
SD cards 16G and larger are only made as class 10 devices. Properly formatting the SD card will improve it's performance.
Onageric said:
SD cards 16G and larger are only made as class 10 devices. Properly formatting the SD card will improve it's performance.
Click to expand...
Click to collapse
No they are not. Here is a 32GB class 4 SanDisk available http://www.mymemory.co.uk/Micro-SDHC/SanDisk/SanDisk-32GB-Micro-SD-(SDHC)-Card---Class-4
artesea said:
No they are not. Here is a 32GB class 4 SanDisk available http://www.mymemory.co.uk/Micro-SDHC/SanDisk/SanDisk-32GB-Micro-SD-(SDHC)-Card---Class-4
Click to expand...
Click to collapse
To be more specific - SD cards 16G and greater are manufactured to meet class 10 standards. To get the most money from their products the production line is optimized to make the fastest and most expensive product. Products that miss the QC marks for "A" grade (class 10) will/should easily pass "B" grade (class 4) specifications. The class 10 data bus can run at faster speeds than a class 4. It can also
r u n s l o w e r, meeting fully the class 4 specifications. Often manufacturers will mark their perfectly good class 10 products as class 4 to fulfill market demands. Think making money.
Onageric said:
Often manufacturers will mark their perfectly good class 10 products as class 4 to fulfill market demands. Think making money.
Click to expand...
Click to collapse
It's seems to be true. Bought "Exployd 4 class micro SD" and it's running at 10 class speed at read/write (always over 12Mb).
See this thread http://forum.xda-developers.com/showthread.php?t=1005633 for extensive discussions of comparative performance of different vendor/model SD-cards. For the purpose of running ROMs, look out for cards with high throughput in randomized read/write access, not in sequential read/write access.
FWIW, I am using exclusively Sandisk class 4, having had terrible results (lots of Wait & Force-Close) with class 10 and 6 cards from a mix of vendors.