Got to agree, I would suggest getting a bigger PSU before you start overclocking components. 300W isn't enough to handle a lot of todays systems, though that does depend on what else you have installed..
- win7 64 bit 6GB be better than 4GB
- win7 32 just 4GB
for all purpose program default non OC : game, Rendering Video,3D D use 6GB or more better
for Overclocking more stable use 2 stick 4Gb good enough