I am writing a program that unfortunately exhibits radically different behaviour depending on whether it's run on an Athlon or an Intel machine.

On the Intel machine, the CPU load is low when the program starts, goes high while some calculations are performed, and then it goes quite low when it finishes. On the Athlon machine, the CPU load is high (100%) all the time.

I've tried this on multiple computers with different Athlon/Intel configurations (although all running WinXP), and the only common factor that causes this problem seems to be Athlon CPUs vs Intel CPUs.

Whilst I would normally suspect a Windows driver problem or some such, the program isn't doing anything really special - just accepting some input over a network socket (localhost, so it's not a network card issue) and displaying a window with the results of the calculation.

All other programs run just fine. Any ideas? Does WinXP have drivers optimized for Athlon that might be buggy compared with their Intel counterparts? Is there a list of such drivers?