http://www.theregister.co.uk/2006/05/18/dell_picks_amd/
Dell to use AMD chips in servers!
Dell Press release (http://www.dell.com/content/topics/global.aspx/corp/pressoffice/en/2006/2006_05_18_rr_000?c=us&l=en&s=corp) (its buried in there somewhere)
AMD Reaction (http://www.amd.com/us-en/Corporate/VirtualPressRoom/0,,51_104_543~108606,00.html)
Expected, Oppys are far more suitable than Xeon in server rigs. Especially when you take large MP Systems all packed in a room together.
As I recall Dell did dabble with AthyMP rigs in their servers for a while as well. They arnt completly devoid of common sense.