Deleted last post due to bad information - Read before reply
This from the asus site
http://www.asus.com/products.aspx?l1=3&l2=11&l3=272&l4=0&model=1276&modelmenu=2
LGA775 socket for Intel®Pentium D/Pentium 4/Celeron CPU
Compatible with Intel® 05B/05A and 04B/04A processors
Support Intel®EM64T/Hyper-Threading Technology
(note. This motherboard does not support Intel Pentium® Processor Extreme Edition. )
Chipset
Pentium 4 processors only - not dual core
Go here for processor compatability
http://processorfinder.intel.com/List.aspx?ParentRadio=All&ProcFam=2112
You'll be looking for Pentium D models at best
More conflicting information here (conflicts with Intel and there own)
http://support.asus.com/cpusupport/cpusupport.aspx?SLanguage=en-us&model=P5PE-VM
Just be careful before buying - certainly no quad support x6800 appears to be highest supported on the Asus site.
That however conflicts with there own information of no "Extreme processor support"