I am currently using a lapped celeron 300A at 505 at 2.2V. The thing is rock stable at this speed. I am using Motherboard Monitor on my ASUS P3B-F but I have noticed that the temp spikes from 53C to 34C quite regularly. This is a slot 1 processor and I am not sure how I can get a more accurate and consistant reading. If any of you have any suggestions please help me. Thanks again.