[Galaxy S II Accessories] Techvir:
My recommendation after playing with all sorts of microsd cards and speeds is to get a sandisk 32gb card ( the new sandisk cards do not show a class speed , except for their ultra and extreme cards - This is their new policy )

Why this recommendation

- Randrom read write is the most important for speed during normal phone performance and i have seen sandisk cards have it the highest .

HERE IS A POST FROM SOMEONE IN XDA. Forgot the source

( quoted from one of the users in xda )

- Lexar class 10 ( I paid 94 $ for this :-( ) has terrible random speeds. The worst infact. Some of the other class 10 cards like kingston, patriot, topram have higher random speeds. However failure rate of some of these cards ( except kingston is high)

- Sandisk 32gb is relatively cheaper and very reliable.

- However if you are interested in regular copying of large files , like for eg : daily trnasfer of lots of music and movie files it might be better to get a class 10 card.

here are some of the links where cards are discussed about

newegg user reviews

http://www.newegg.com/Product/Product.aspx?Item=N82E16820220547

amazon user reviews

http://www.amazon.com/Lexar-MicroSD...dp_top_cm_cr_acr_txt?ie=UTF8&showViewpoints=1

xda discussion about various class of cards

http://xdaforums.com/showpost.php?p=13161740&postcount=26

Editing to add more information

The link below is to the speed testing of many micro sd card. Very useful

http://forums.whirlpool.net.au/forum-replies.cfm?t=1582172

I am pasting the info from that thread here

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Some test results posted in this thread

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Patriot 32gb class 10

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CrystalDiskMark 3.0.1 x64 (C) 2007-2010 hiyohiyo

Crystal Dew World : http://crystalmark.info/

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* MB/s = 1,000,000 byte/s [SATA/300 = 300,000,000 byte/s]

Sequential Read : 19.282 MB/s

Sequential Write : 10.477 MB/s

Random Read 512KB : 19.071 MB/s

Random Write 512KB : 1.059 MB/s

Random Read 4KB (QD=1) : 7.335 MB/s [ 1790.7 IOPS]

Random Write 4KB (QD=1) : 0.247 MB/s [ 60.2 IOPS]

Random Read 4KB (QD=32) : 7.232 MB/s [ 1765.7 IOPS]

Random Write 4KB (QD=32) : 0.259 MB/s [ 63.2 IOPS]

Test : 100 MB [H: 47.0% (14.0/29.8 GB)] (x3) <All 0xFF, 1Fill>

Date : 2011/06/19 11:02:22

OS : Windows 7 Home Premium Edition [6.1 Build 7600] (x64)

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SanDisk 8GB Class 6 for comparison, 2 years old.

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CrystalDiskMark 3.0.1 x64 (C) 2007-2010 hiyohiyo

Crystal Dew World : http://crystalmark.info/

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* MB/s = 1,000,000 byte/s [SATA/300 = 300,000,000 byte/s]

Sequential Read : 21.241 MB/s

Sequential Write : 17.626 MB/s

Random Read 512KB : 20.846 MB/s

Random Write 512KB : 4.629 MB/s

Random Read 4KB (QD=1) : 5.356 MB/s [ 1307.5 IOPS]

Random Write 4KB (QD=1) : 0.052 MB/s [ 12.7 IOPS]

Random Read 4KB (QD=32) : 5.484 MB/s [ 1338.8 IOPS]

Random Write 4KB (QD=32) : 0.058 MB/s [ 14.2 IOPS]

Test : 100 MB [H: 89.2% (6939.2/7782.5 MB)] (x3)

Date : 2011/06/19 0:47:33

OS : Windows 7 Ultimate Edition SP1 [6.1 Build 7601] (x64)

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32GB Class 4 Sandisk.

Tested results when I received it today and thought I would post the results in case anyone else is considering purchasing from the same source.

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CrystalDiskMark 3.0.1 x64 (C) 2007-2010 hiyohiyo

Crystal Dew World : http://crystalmark.info/

-----------------------------------------------------------------------

* MB/s = 1,000,000 byte/s [SATA/300 = 300,000,000 byte/s]

Sequential Read : 20.071 MB/s

Sequential Write : 6.088 MB/s

Random Read 512KB : 19.716 MB/s

Random Write 512KB : 0.625 MB/s

Random Read 4KB (QD=1) : 3.234 MB/s [ 789.5 IOPS]

Random Write 4KB (QD=1) : 1.467 MB/s [ 358.2 IOPS]

Random Read 4KB (QD=32) : 3.164 MB/s [ 772.4 IOPS]

Random Write 4KB (QD=32) : 0.150 MB/s [ 36.5 IOPS]

Test : 1000 MB [E: 1.9% (0.6/29.7 GB)] (x5)

Date : 2011/06/27 19:34:44

OS : Windows 7 Home Premium Edition SP1 [6.1 Build 7601] (x64)

29.71gb Capacity

SD Tools results:

writing speed 6.2mb/s

reading speed 21.7mb/s

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Just adding somemore info on some the cards i have

FINALLY 64GB CARD

http://www.geek.com/articles/mobile/kingmax-intros-worlds-first-64gb-microsd-card-20110526/