Also, limiting access to 3.2 gig out of four causes problems for dual channel memory (2X2 Gig) it is possible your audio can drop out because of allocated ram locations being in the unread bit,(been there, scratching my head) and you can lose efficiency on your bank interleave (dual channel) performance bonus. I dont want to bore you fellow intel user, shall we just say use 64 bit?
I would and not worry further.