After reading through what he's posted im gonna go out on a limb here and suggest a Check of the cpuid limit option in his bios, I had a maddening problem out of a dell 8400 once where no matter what i did it took Ages to do anything.
(mouse cursor would redline the taskmanager)

Biostars its called CpuidMaxval Enable/Disable
Dells its cpu compatiblity mode enable/disable
Asus its Cpuid limit or 03h enable/disable


Look for anything called cpuid limit or 03h enable/disable and make sure it is OFF
or you will be waiting.