Can you please post the output of: from your N900?

13MB/s would be quite disappointing, but the USB 2.0 connection to the PC wouldn't deliver much more anyway. Can you please post the output of:?

He said he used the (N900's) default file manager, not the SDXC's default file system.
So I guess he formatted the card with Fat32 (fdisk will tell us). In principle Fat32 is 64GB-capable, but older Windows versions aren't.

I bought one of these. When you put the card in the N900 it doesnt work straight away. It simply says unsupported format.

How he managed to get the N900 to format it (if he did) I dont know...

Well, probably it's formatted via exFAT, so You just need to fomat it using ext or fat32.

It seems, that simple 'losetup [device] [/dev/[some_loop]", then "fsck.[whatever] [some_loop]" will do.

/Estel

Got mine working..am amazed:

Insert Card. Ignore Card Format Not Supported message.

Menu
File Manager
Memory Card (Long Press)
Format
Yes

See: http://twitpic.com/8eap98

Have to say though, transfer rates are pretty poor. It appears that the N900 formats using FAT32 which doesnt seem to suit the card at all.

Just taken 4 minutes to transfer 1.78gb...not too good!

"genuine" Sandisk 64GB MicroSD SDXC has been out for a while.
I assume he meant he formatted using N900's file manager.
So it should have formatted it as FAT32.

That translates to about 7.4MB/s. Indeed not very impressive but then again that card is only labeled as class 6 so anything above 6MB/s is a bonus.
Try formatting it with ext2! That should bring some performance gain compared to fat (maybe an MB/s or two if you're lucky).
But realistically we won't see any exceptional numbers with that card anyway.
I'd estimate the limitation on the N900 side at about 30MB/s, so buying SDXC cards for transfer rate reasons doesn't make much sense before they actually make use of the UHS-I standard.

Yeah, but how quickly can it random read/write 4K blocks?

1: Why is that important?

2: Is there a way to test this?

Thanks

It is important because while it may have a 'mediocre at best' sequential copy speed, it may have a totally badass 4k random block read write speed.

You see, SD card 'class' is a pile of total non-sense peddled by certain manufacturers to appeal to the number obsessed 'pro-sumer' (read: techno-mongo).

Generally hardware manufacturers will bodge something in order to get these super high SEQUENTIAL read/write speeds at the expense of random small block read writes.

If you want to just copy movies and photos to/from the card then this is great. If you however want more from your card i.e. to use it as program storage, swap space or to host an OS small block random read/writes are more important. The best example I know is this.