Hey I have a i9300 with a 1.86G processor. I want to upgrade my memory to 2 gigs or RAM but am unsure about the type. I know it takes SODIMM DDR2 4200 533MHz for sure, but how come some have a different number of pins, i.e. 200 or 240? Which is better or is there any difference at all? Also can I use two 5400 667 MHz instead? Thanks for your help!