I just got an old HP Pavilion a1610n from a friend who was trying to get rid of it, and I'm trying to fix it up. The processor, an AMD Athlon X2 4200+, is rated for 2.2 GHz. I've tested it and found that in Windows XP, the processor only runs at 991 MHz. In Ubuntu 9.10, it starts out at 2.2 GHz, but then drops down to 1 GHz after displaying this message: "Clocksource tsc unstable".
This only seems to happen on Linux kernels that have SMP enabled. On a Clonezilla 1.2.2 live CD, /proc/cpuinfo shows only one CPU, and the clock frequency stays at 2.2 GHz and never drops down.
What could be causing this? Is it most likely an issue with the processor or the motherboard?
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