If you already have the 800FSB cpu, then you would need a mobo, that supports EEP4's and the 1066FSB. Performing the 'pinmod' will bump the cpu up to the next strap, and increase its FSB and default clock.
There are also pinmods for vcore adjustments, for use on mobo's that so not offer vcore settings.
If the processor is 400 fsb based we can run it at 533 fsb by insulating pin AD6. The High status of the signal therefore becomes LOW when not connected on board. This indicates that it is a 533 fsb processor to the system bios.
Likewise a 533 fsb P4 or Celeron CPU can run at 800 fsb by insulating BSEL1 pin at AD5 pin. Thats a very good and easy trick.
BSEL0 mod (insulation of AD6 pin) provides step up from 400 fsb to 533 fsb. [RIGHT!]
BSEL1 mod (insulation of AD5 pin) provides step up from 400 fsb to 800 fsb. [RIGHT!]
AD6 pin modding for BSEL0 gives a 400 fsb CPU to 533 fsb CPU speed. [Right!]
AD6 pin modding for BSEL0 gives a 800 fsb CPU to 1066 fsb CPU speed. [Right!] If becomes available!
I will try to load some pics if I cannot find the links.