If you have a specific need, then great - I ran some old 486 machines until
about 2003 as they were just doing a simple job using a DOS application. It
was the equipment they were connected to which went unsupportable first!

It looks like the motherboard is for a Celeron, so given the age, and the
fact the earliest 266 Celeron didn't have a L2 cache, it could be anything
between 300Mhz and 533Mhz.

You should be able to confirm from the chip if none of the other methods can
correctly identify it. See
http://www.oldcpu.cz/CPU/Intel/Celeron-PPGA-socket-370

Midge.