BF0 and BF1 signals are simply sampled by the CPU at reset which sets the multiplier

Please note that "0" in the above table means having low signal which typically means having a respective motherboard jumper closed as jumpers often shorten the pin signal to ground.

There is a different logic for the 233 MHz CPU and 3rd party models.

Many Socket 5 boards don't have a BF1 jumper as it was defined for 150MHz CPUs which did not exist back then.

If not connected/supported by MB those pins are internally pulled up by the CPU. Thus you get "1" on old motherboards.

I made this for another thread:

The green dot and arrow mark BF0, BF1 is the blue dot, BF2 is the red dot (on CPUs that support BF2).
To pull the signal low (i.e. set a jumper) you need to connect them to Vss. I marked the nearest Vss pins white with a black dot.

Oh, and on socket 5 usually leaving the multiplier jumper open will make a S7 Pentium CPU run at 3x because BF1 is always high/open.

That's great! Thank you!

Cheers,

This is for Proliant 1500 hardware.

Good news, I found the resistor with correct resistance and checked BF0 and this resistor and does goes to ground via 100 ohms located R25 next to this is R26 which is left unpopulated which is pulled up by 3.3V rail. I'll move this resistor to R26 to pull BF0 high. I have not found the other spots for the BF1 and it is assumed open since I cannot find either ground or 3.3V connected to the BF1. Likewise for BF2 which is also open.

There is solder pads for 4 switch for setting fsb and there is silkscreen saying 100, 90 and 75 which meant 66, 60 and 50MHz fsb. Other 2 positions is undocumented.

Update after moving the resistor from R25 to R26, now reports as 200MHz instead of 166.

Cheers,

Great! Interesting that they decided to configure the board in a way the user couldn't change the multiplier using a jumper.

This processor card design is same for Prosignia 300 and 500, mod them these too.

Cheers,