I just bought a n800 off ebay. It came with a 4gb class 4 and a 8gb class 6 SDHC. They seem awfully slow in the n800. The "about product" screen says I have OS2008 version 2.2007.51-3. Do I need to update something or change some settings?

hdparm for both cards gives on average:
/dev/mmcblk0:
Timing cached reads: 176 MB in 2.01 seconds = 85.68 MB/sec
Timing buffered disk reads: 18 MB in 3.07 seconds = 4.93 MB/sec
Nokia-N800-51-3:~# ./hdparm -tT /dev/mmcblk0p1

hdparm for internal memory:
/dev/mtdblock4:
Timing cached reads: 176 MB in 2.02 seconds = 87.33 MB/sec
Timing buffered disk reads: 46 MB in 3.18 seconds = 14.48 MB/sec

Slow is typical

I'm not sure how much it helps, but you can try looking into high speed kernels.

Could someone tell me whether diablo still get the poor sd performance or not?

I was searching for kernels that have been patched with the 48mhz SDHC mod, but I couldn't find anything up to date. Anyone have a link to the latest high speed kernel?

http://intr.overt.org/4.2008.23-mmc-kernel/