Seem to have hit a wall

I can't get past 248fsb with my current setup. I'm using Buffalo pc3700 (yes it's bh-5) at 5/4. and can with tight or loose timings and I've passed 10 lops of memtest with respective timings at 248fsb. Anything over 248fsb and I get freezes before I get to the desktop. Temps are good to go: 34/36c idle and about 47/48 load.

My cpu is a 2.4C SL6Z3 fpo/batch: 3328A517

I've tweaked and tweaked and tweaked some more. What I was wondering was if maybe the buffalo was the hold up? (running at 3.0v) I was thinking of buying some mushkin PC3500 lvl II to see if it makes a difference. Other choice I guess would be to try another cpu. Either way it's $$$$ so it's one or the other.

My goal with this rig was to run a nice and stable 255-260fsb.

Your thoughts? thanks!!!

Is the Buffalo PC3700 running into the same problems when you try 1:1? How high up, with 2-2-2 timings, will the memory run while at a 1:1 FSB:MEM ratio? If you are using two modules, try running with each of them by themselves, and see if it's not one of them holding you back.

test out the cpu to make sure it will run over 3 gig first. use 1 stick at 3/2 with loose timings. once u determine the cpu is capable of running that fast, then test each stick in single channel with loose timings at 1-1 ratio to determine if each is capable of 250 or greater. right now they arent even hitting 200 mhz. to me your problem points to a cpu that wont oc well or a bad stick of memory.. goodluck