The link on that page is broken. To find out the limitations of
running FSB800 Northwood processors on the P4PE, go here:
http://www.asus.com/products/mb/fsb800.htm
To use a FSB800 0.13 micron processor:
1) Upgrade the BIOS to 1006 or later revision, before installing
the new processor.
2) When running at FSB800, you are limited to one stick of DDR400
memory. That is because the chipset runs synchronous, and clocks
the processor and memory with the same clock speed. The best
you could do, is to find a 1GB DDR400 DIMM, with CAS2 64Mx8
memory chips on it. If you add more sticks of memory than a
single DIMM, you will see memory errors. Test with memtest86+
from memtest.org .
The typical user experience with this idea, is that the motherboard
barely works at FSB800/DDR400. The memory will not go more than a
few MHz faster than the DDR400 rate. In some cases, you have to
adjust the clock to give slightly less than FSB800, to get stability.
The Asus cpusupport page shows 3.2Ghz processors as being the top
speed, which will give you a slight improvement over your 2.8Ghz
processor. Running the memory a bit faster will help about 5%.
HTH,
Paul