WCIF a fast SD card?

I want to get a 2 or 4GB SD card to use with Vista’s Readyboost feature. I just tried putting in a Toshiba-branded one I bought from Cankun 3C, but the system reports that the card’s performance isn’t good enough.

According to the Wikipedia article on Readyboost, these are the required speed and compatibility specs:[quote]# The device should have an access time of 1 ms or less

The device must be capable of 2.5 MB/s read speeds for 4 KB random reads spread uniformly across the entire device and 1.75 MB/s write speeds for 512 KB random writes spread uniformly across the device

NTFS, FAT16 and FAT32 are supported

The initial release of ReadyBoost supports one device[/quote]

Any idea where I can find a compatible SD card? I’m not sure whether these specs are listed on card packaging, and as I’m a bit pushed for time I don’t really want to go searching around different shops.