i Tested different sector sizes for sd card 4GB in size with VFSmark
and there is no difference in the VFSmark score but there is a lag difference.
4k sector size makes the 700p very laggy and slow to respond which is the default sector size for FAT32 in a 4GB volume 16k sectors removes alot of the lag and the 700p is more responsive. the reason behind this i believe is that at 4k sector size a 4GB sd card has around 1,000,000 sectors at 16k there is 250,000 sectors a 2GB sd card is formatted as FAT16 and defaults to 32k sectors which would have 62,500 sectors and I think the 700P has a hard time accessing the SD card when there is a lot of sectors.

My 700p is a bell phone and according to palm has most of the updates in the MR so your results may vary but i would suggest 32k or 64k sectors on a 4GB or higher SD card.