On the clock gen, the sixth pin from the pin 1 mark. Looks like you set the jumpers to 55mhz then follow the trace coming off that pin and it probably goes to a resistor. Use a hot air gun to remove the resistor and you should be set to 75mhz. Or lift that leg.

(At your own risk), though it’s not risky as long as your solder skills are up to it. That’s just a config register. It just looks for voltage or ground. Hopefully it interprets open as opposite. Either way, shouldn’t hurt worst case you have to run a pull up or down resistor over to that pad after removing the resistor

I can’t find anything for that vrm controller if even that is what it is. Can anyone else find a datasheet?

Try removing all the p55/p54c jumpers and see what you get for vcc2 to ground. (Outer pins, middle one in the notch on the socket, use a resistor leg)

https://www.ultimateretro.net/motherboard/manual/33938.pdf

Bingo!

Settings down to 2.5v

This means you can do k6-3 (non plus)

Also highly suggests undocumented settings probably down to 2.0v for k6-3+

Most likely you’ll have to test and document them yourself though. Even if we did find the data sheet. Start with all voltage related jumpers removed. Note base voltage, And install one and note the value increse, remove it. Install another, note the increase, and so on and so forth until you find what will most likely be

2.0v base
+0.1v jumper
+0.2v jumper
+0.4v jumper
+0.8v jumper

After all this, your final step will be a bios update

DIY Bios Modding guide Jan Steunebrink k6-2+/3+ 128gb

A k6-3 will probably work without a update, but work better with. Results vary though.

As for getting a k6-3+:
SUCCESSFUL K6-2+ to K6-3+ Full Cache Enable Mod