My operating system is Windows XP Home SP1. The processor I'm using is an AMD Athlon XP 1800+ on a mobo with a VIA KM266 chipset. The spec sheet for my processor says that it's clock speed is 1533 MHz. When I right click My Computer, it says 1.53 GHz along with my 512 MB RAM. However, when I view system info, or use any hardware monitoring programs, it says my processors current speed is 1529 MHz, and that's a stable reading. When I boot my computer, BIOS says that it's clockspeed is 1533 MHz. Did I actually lose 4 MHz, was AMD's spec sheet just rounded up, or is there a bug in Windows XP that could say this? (And no, I've never attempted overclocking or any modifications, the processor never went above 46 C as the machine would warn me, and if it hit 50 C it would reboot. So it's not like the processor was "abused"). Thanks for your help / info.