I'm running Samba on an Overo Earth. The Samba share is on the SD card, in a FAT partition (since I expect faster reads/writes on FAT). Using a 16GB MLC (multi level cell) card, I see write speeds to the share of >500KB/s. However, with a 4GB SLC (single level cell) card, I only get about 30KB/s. Performing copies or other operations (like tar) shows no major discrepancies in the cards' read and write speeds. It seems I only get this massive slowdown when writing via Samba.

Any ideas on what the problem could be?