Getting 4 sticks of OCZgold to 430MHz from the stock 400MHz maybe all you're going to get there. OC'ing 4 sticks usually will net a top FSB sooner than 2 sticks, try taking two out and see if that helps. If it does then you know it's RAM holding you back and a faster set may be in order. G.Skill has their 2x2GB 500MHz stuff pretty cheap.
__________________ Q6600 @ 3.83GHz w/ D-Tek Fusion
Asus P5Q-PRO
2x 2GB PC8000 Mushkin Redlines @ 1020MHz w/5-5-5-12 timings
EVGA GTX 280 (SC?)
OCZ Gamer Xtreme 600W PSU
Cooler Master Cosmos on water |