I have my B core running and have been playing around at different speeds, fsb and volts. I thought it was stable because P95 runs mint all day and once in a while I will BSOD? I got memtest and found at 180 FSB and above this Samsung is crappin out. I just ordered some pc3500 Hyper X 256 modules to replace these. Think it will help? I'll keep you posted. BTW this is the best overclocking cpu I have ever seen.