dude ures cant even pass 5 loops on less ram..

what u think is going to happen with more ram ( longer period)
64 bit is the best way to test...

32bit is like half testing... somewhere down the road.. some crash is going to happen in some long period of stressing some component... and u will never know...and ure going to be b****ing that linpack /orthos/prime doesnt mean stable..
go to start
run
type msconfig and press ok
choose diagnostic mode...
press ok...
and restart..

2gb is okay.. cause in diagnostic mode u will still get about 1.7-1.8gb worth of ram free to test...

anyway this is afar as i am gonna tell on this..
use google..