I just got my retail cel566 today. I put it in my Asus Slocket, set the jumpers to 1.50 v and booted up to Win ME at 850. I got a BSOD when I was playing SOF, so I upped the voltage to 1.60 and it is running solid now. I used the Intel heatsink and fan that came with it, but I used some radioshack grease instead of the pad that is on the HS. My system is now running much cooler than it did with my 300a@450 2.00 v. I am very pleased with the chip. I think I can push it higher, but my el cheapo RAM might hold me back. Good luck.