now this is odd...
I can O/C to 240mhz FSB with ram speed at 266mhz
but once I change to 400mhz computer doesn't boot.
and with no O/C i can change to 400mhz and computer now boots fine...
i dont know why my rams wont run at ddr 400 after overclock
Yes, Amino got me on that one - change the cpu:mem ratio. At a 1:1 ratio I've never been able to set the fsb much higher than 215mhz - I'm running on pc3200. I can't imagine that pc3500 would allow for as high as 240mhz so switch the ratio to DDR333 in the bios, then bring up the fsb until the ram is maxed out.
While we're on the subject, I'm still new to oc'ing and I haven't really played with the ram timings too much. When I think I'm at my max oc I've made the ram timings both as relaxed and aggressive as possible - setting them more aggressive definitely didn't help, more relaxed didn't allow for a higher oc. Is there anything else I could do with the timings to produce a higher oc?