Hi,

On my BX board QDI P6I440BX/B1 Brilliant -I, I wanted to have 133 MHz.

I first started with something simple whic has nothing to do with the FSB.
I added MAX1617A temperature monitor chip, the CPU temperature measurement automatically appeared in BIOS

And because of my Tualatin CPU, I also updated the microcode database in the BIOS.

The board has a PLL clock generator Cypress W48S111-14 which can go only up to 133MHZ FSB, but PCI is at 44 MHz. But this choice is not available in BIOS anyway.
So I swapped it for Winbond W83196S-14A, which has more choices of FSB frequency up to 160 MHz among which is also 133 MHz FSB with regular 33 MHz for PCI bus.
Unfortunately swapping chips has not unlocked any more FSB possibiliites in BIOS.
I also changed the original Clock Buffer/Driver Cypress W40S11-23 with Winbond W83178S. The original works up to 133 MHz, but the replacement, though the first page of datasheet states 100MHz, is able to operate at 150 MHz according the declared time propagation delay value.

In this age of AI, gave it a chance.
It was able to modify the BIOS and add more FSB choices. It wasn't painless but finaly it did it.

I also asked to add a Award and EPA logo which were removed by QDI, due to the option of fullscreen QDI logo.
We had to cheat a bit to switch to EGA mode and dissect the graphics into glyps, but it worked.

Here is the mentioned BIOS, with the complete documentation of the modification.