overclocking E6750

CPU: E6750
MoBo: Asus P5B
Memory: 2x 1GB GEIL ULTRA 4-4-4-12
cooling: Zalman S9700

So far I managed 3.2GHz without increasing voltage. and now I hit a brick wall. it seems that I can't set lower memory multiplier than x2. I set FSB to 400MHz and DDR2 to 800. trying to go up results in prime95 freezing system. I think it's the memory which can't go faster than 800MHz but I'm unable to set memory speed to anything lower than 2x FSB speed. it can only go faster. setting slower timings on memory didn't help.

any suggestions what else I could do?

all right, now I got it. it can only go faster than x2.

but I'm still wondering if there's anything possible to do to make it run faster? does anyone have some experience with this memory? is it possible to make it run at more than 800MHz?

and maybe it's not memory problem, what should I try next?

so far it's stable at 3.2 GHz with Vcore at arouund 1.25-1.28V. if I give it more voltage will it make it stable at 3.3GHz?