i've heard differing opinions on this - i asked the question regarding the OMNIA HD, which i was told that CLASS 2 was ok even for HD playback, maybe an issue for recording though..

Playback isn't as intensive as recording. Where class shines is the writing speed (though of course it's also faster at reading). Things like recording something, or swap on the tablet, something that involves writing to the flash memory would benefit the most from a higher speed class.

16GB class 2 will take a few hours to load if you're loading up the entire thing...

Just thought i'd start this thread up again now that the lucky 300 have N900's to play with.
Has anyone noticed any dropped frames when capturing video, or similar problems when using a class 2 card? If so, did using a faster (i.e. higher class) card correct it?
Thanks for any info. Just wanted to check that my current class 2 card isn't going to be a bottleneck in the N900 hardware.

I'm wondering about the recommended SD Class, too. At what point does the hardware become the bottleneck vs the speed class of the SD Card?
8GB class 4 & 6 are commonly available. I've seen Class 8, but rarely. Unless I hear otherwise, I'll likely get Class 6.
Any issues with SanDisc compatibility? There was a thread discussing N810 issues reading SanDisc SD cards.
Steve

Looks like more people have received their N900s.

Any word on whether the N900 will fully utilize the speed advantage of a Class 6 Micro SDHC card? Or does the N900 bottleneck the card and if so, which class is the cutoff performance-wise?

I have a SanDisk class 6 8GB in my N900, need a way to test it. dd?

well a very informal test:

dd if=/dev/zero of=test.dat bs=1024 count=100000

took 20 seconds to create a 102,400,000 byte file.

Class 2 means it can do at least 2MB/sec read/write,
Class 4 means it can do at least 4MB/sec read/write.
Class 6 means it can do at least 6MB/sec read/write.

http://www.sdcard.org/developers/tech/speed_class/

But most Class 2 cards can easily do at least 6MB/sec these days.
My Class 4 Sandisk card can do 14MB/sec write and 18MB/sec read.
My vanilla Class 2 Sandisk can do 7MB/sec write and 12MB/sec read.
My no name Class 4 card can do around 12MB/sec both read/write.
(At the end, pretty much ALL cards meet Class 4 and most exceed Class 6 even if it say sit's Class 2)

So.... These 'low' Class 2/4/6/ values are completely useless....

Another example:
- 1080p AVCHD video records at up to around 25Mb/sec in most HDvideo cameras. (Note the small "b" for bit) So that's around 3MB/sec (big "B" is Byte). It would be extremely difficult to even find a card that cannot do 3MB/sec. Even the dodgy ebay ones included.

So these days, unless you want SUPER fast card to be used with a SUPER fast card reader to do more than 20MB/sec, you don't need to worry about "Class" specification as nearly ALL cards these days are at least as fast as Class 6 specifications in almost all cases. (Except for maybe dodgy ebay fake cards)

It's just that there are cards which are MUCH faster than Class 6 and there are cards that are just a little bit faster than Class 6. But those who have such high requirement should know about this already and buy the appropriate high-end cards that promise that specific speed accurately and have the equipment capable of taking advantage of such speed. (eg. Expensive memory card reader and fast DSLR etc)

Can anyone test the internal memory (MyDocs) vs. a class 6 microSD? I want to confirm my suspicions.