Hello and welcome to the forums
Here is from HP's sitehttp://h10025.www1.hp.com/ewfrf/wc/document?docname=c00906129&lc=en&cc=de&dlc=&product=3397528#N961
"Motherboard supports the following processor upgrades:
Athlon 64 X2 with Dual Core technology up to 5600+ (up to 89 watt)
Athlon 64 less than 4000+
Sempron less than 4000+ "