This is a reference to THIS POST. I have not gotten any replies to that post for a while, so I felt it would be ok to start this thread. I am pretty sure I have determined for sure that the processor is at fault. When I set the BIOS to 900 MHz default speed, 100 Mhz bus speed, normal mode, the system seems to work flawlessly. I was online for about 5 hours yesterday with no system freak outs, illegal op, or fatal exception BSD's at the default speed. I briefly ran the system at normal 1200 MHz speed today. Firefox closed w/ illegal op error within 5 minutes. I restarted, reset BIOS back to 900 MHz default settings, rebooted. This was over an hour ago--again flawless operation at that speed. So, the problem has to be the processor is not executing certain instructions correctly at the faster speed, causing a divide by zero or other error. Currently the MoBo is of course set to jumperless mode and I have had it set on jumper mode in the past. All that mumbo jumbo brings me to my question: Though the MoBo officially only supports up to 1.2 GHz, it seems to me that I could set the system up for jumper mode with a 133MHz bus speed and 10x multiplier, allowing me to run a 1.33GHZ CPU. The reason I thought about this is that I can't find a merchant I feel comfortable with who has a 1.2GHz chip, but my favorite merchant has the 1.33GHz/266FSB chip in stock for $43. The only listings I could find for the 1.2 GHz CPU, and I looked everywhere, were 2 who both had a lot of bad reviews on resellerratings.com. I found it on ebay, but I basically felt that the sellers were trying to unload their junk. I don't want to have to change good memory, motherboard, and probably video card also in order to replace a flaky CPU if I can avoid it. Can I use the 1.33 GHz chip? If so, what are the potential problems? If I can use this chip, I probably need to get it ASAP, before it sells out. Motherboard documentation is linked from the ASUS website.