get a set of 2x1 or 2x2 pc 6400 4-4-4-12 sticks. the 2x1 were around $30 AR last time I checked and about $65 for 2x2, so it's incredibly cheap right now. get the highest OC you can get on the 8x multi, then try to fit your memory timings around that. I have ddr2 1066 ballistix in my x3350 rig running at 8x450. I have it at a 5:6 multiplier so the memory runs at 5-5-5-18 1080. My Q9450 is only at 8x425, however, with 4-4-4-12 ddr2 800 memory, but it runs fine at 4-4-4-12 with 1:1 (850).