PROBLEM: crazy timer on dual pentium-mmx (2.4.5 and 2.4.6)

hello,

I have a serious problem since 2.4.5 kernel, the timer go crazy (about 10 time normal speed)
I can't login because the 60 secondes timeout get only a few second in real life.
Same thing about harddrive timeout error.

The motherboard is a dual pentium-mmx 200

http://www.asus.com/products/motherboard/pentium/p65up5-p55t2d/p65up5-p55t2d-spec.html
http://www.asus.com/Products/Motherboard/Pentiumpro/P65up5-p6nd/c-p55t2d.html

kernel is compiled on the computer with kernel 2.4.4 and following tools:

Gnu C                  2.95.2
Gnu make               3.79.1
binutils               2.9.5.0.37