http://www.pspmod.com/forums/psp-har...-answered.html (Photofast CR-5400 - questions answered!)
Check that post m8.
About the SDHC cards, the higher the Class, the faster the supposed transfer rate. There's a bit about that in the link as well. I personally use 2x Class10 MicroSDHC cards @ 16gb a pop.
(Class 2: 2 MB/s; Class 4: 4 MB/s; Class 6: 6 MB/s* etc. etc.)
Hope that helps.