Gigabyte HD4650 agp on k7n2 - poor performance

I recently bought Gigabyte HD4650 , agp interface, and installed it on a MSI k7n2 mo. The card performs poorly in relation with the previous card I had, a nvidia geforce6600 gs. The cpu is AMD xp2000 , clock runs OC at 145 MHz. 1gb RAM, kingston PC3200. Any ideas?

145 MHz? I hope there ewas supposed to be a decimal point and a G in there somewhere. The reason it performs so poorly is that its drivers have slightly higher overhead, not a significant issue on modern system, but a very significant issue when your CPU is going that slowly. You can get a vastly superior system for only $500 that will actually let you play modern games.