Proof of Concept: 1066 fsb CPU on a PM965

Now we all know that a PM965 northbridge will not POST given a 1066 fsb cpu (800 fsb max).
We also know that the reason for this is that a PM965 is programmed to shut down when the BSEL pins are configured in an unsupported state (reserved).
At 266mhz fsb (quad pumped to 1066) the BSEL pins are L L L.
At 200mhz fsb the BSEL pins are L H L (listed as BSEL2,BSEL1,BSEL0)
We know that PLLs can be pinmodded to break the BSEL1-PM965-FS2(PLL) connection.
So to get 1066 fsb and POST we break the FS2 connection on the PLL so we have BSEL1-PM965 | FS2(PLL).
Then we do a FSLx mod on that pin of the PLL (Drive it low, I used 70 ohm to ground).
In addition, we drive the BSEL1 pin high with a pinmod (connect BSEL1 to Vcc on the CPU socket).
The PM965 sees L H L (200 mhz) and boots as this is acceptable.
The PLL sees L L L (266 mhz) so it takes the processor to full 1066 speed.

If anyone would like to donate a 1066 fsb processor, I will do this mod and report back here on results.

 

Why don't you purchase one from ebay?


--

 

I already have a T9500 so any 1066 CPU would purely be for test purposes (unless someone wants a swap with my T9500 instead...

 

I would trade you.
I don't have a 2.6 though, only a 2.4, 2.53 and 2.8ghz

 

You should also try something similar first to try and overclock your current CPU. I think you can guess what I mean?

I think you have missed 1 important step, that is BIOS microcode.