Problem with front side bus (FSB)

[Wireframe]

This is a really strange problem, and i don't understand it.

Well, sometimes when i turn on the computer FSB is set to 100 mhz, and because of that the processor is working only with 1100 mhz (multiplier is 11). And only occasionally is working with full power thats 1836 mhz,when this happens FSB is set to a normal (factory) value and that is 166 mhz.

Why is BIOS (or I don't know what) changing value of FSB?
I have never overclocked the processor. What can i do?

And the processor is: AMD Athlon 2500+ XP

 

[87dtna]

Perhaps try a bios update on the motherboard. Or, the board is on it's way out. It's pretty old.

 

[Wireframe]

What's old? The motherboard? The whole computer is old, but it should work on the primary frequency.

 

[87dtna]

Motherboard is old, it causes instability.

 

[StrangleHold]

Ever replaced the CMOS battery? Could be dying and freaking the bios out. Just a few bucks.

 

[87dtna]

Ever replaced the CMOS battery? Could be dying and freaking the bios out. Just a few bucks.

Nice! Didn't even think of that.