Originally posted by boheemee
this is an excerp from a review at: http://firingsquad.gamers.com/print_...rticle_id=1268

For manual bus speed adjustment, settings range from 100-400MHz in 1MHz increments, offering tons of options for the enthusiasts out there who wish to overclock their P4P800 Deluxe system.The memory bus and AGP/PCI frequencies can be locked at specific speeds , another must-have item for successful overclocking. And while the original P4P800 Deluxe BIOS was limited to just 1.7V for CPU core voltage adjustment, the latest 1006 release offers settings up to a whopping 1.95V in 0.025V increments.

Most likely a bios setting...
I have the P4P800-Delux and havent foudn how to lock it even with the most updated Bios. I also dont know alot about BIOS though and really dont like messing with it all that much.