Ages ago I upgraded from an Athlon XP 1800+ to an 2400+. Did bios upgrade no probs. I'm fairly sure it was initially showing correct speed of around 1.9 - 2.0GHz. Recently had XP crash and had to do full install. CPU speed is now showing as 1.51 GHz (isn't that what my old 1800+ was?), but BIOS is still showing as the latest version and "System Properties" shows it as a 2400+. Any ideas what's wrong or how to fix it?
Just had a look and I'm totally wrong, sorry. The 1800 runs at 1533 the 2400 should run at 2ghz and my one because its a different design runs at 1833. So I think fred may be right check your FSB. click here