The two upper unmarked holes (from bottom to top) are used to set CPU multiplier - BF1 and BF0, but that MB already has jumper headers for all possible multiplier combinations. Either previous owner was experimenting with CPUs or MB has problems with CPU multiplier selection jumper header/CPU socket 😀

The mobo doesn't have 3.5x, or it was not documented. If that jumper tricks gets you there, I wish I'd known 20 years ago. 😀

Edit: 3.5x Pentiums interpret 1.5x as 3.5x. I don't suppose that's something you can switch with a wire(?).

firage wrote:

If that jumper tricks gets you there, I wish I'd known 20 years ago.

Same here, i've been using a socket 5 system with 150 MHz P1 @ 100 MHz the whole time back then, because it had only documented 3 CPU frequencies inside the case, 75, 90 and 100 MHz, fun times...

Thanks for that. I kinda hesitate to try any CPU on it if I don't know for a fact that I can remove this wire. I don't have many extra CPU's and I'd rather not fry any of those with a bad board.

It only has two multiplier select jumpers BF0 and BF1, so you need the mod for third jumper BF2 so you can get certain K6 CPUs to run at correct frequency with certain FSBs because standard two jumpers kind of expected you had a certain FSBs available.

Back in the day I owned a T2P4 (forgot which exact revision) and also had to mod it to get the rated frequency for the K6 part I had (also forgot exact model and speed). It's possible I actually did not need the mod for standard 66 MHz FSB, but maybe for experimenting with 50 or 75 MHz FSBs, even if it was not meant to go past 66 MHz.

Edit:
Seriously, the exact page I used has been archived by someone, too bad other T2P4 stuff like selecting voltages that are not on the standard list is not there:
https://etmriwi.home.xs4all.nl/adding.htm