I've got a K7D Master that i've been running a pair of 1.8 applebreds in, but I upgraded to MP2600s and the CPUs came yesterday. Dropped em in, reset everything, but I freeze up in windows (well if I even get that far) when the FSB is set to 133. I can run 100 all day long, but the 133 kills it. Had this same issue with the applebreds, but I just attributed it to crappy CPUs and heat issues. I'm running a stick of 512 PC2700 ECC Registered DDR, and the issue still occurs with some PC2100 non-ecc stuff i've got lying around. I played around with the vCore, and that helped get into windows more reliably (set to 1.675), but still it freezes once I run anything. I've got a more than adaquete supply for the system, a Vantec Stealth 520, and my cooling consists of one Vantec Aeroflow, and one stock copper-base retail cooler, which is being replaced by another Vantec Aeroflow friday. Any ideas?