the only real differences (that i know of) is the chipset (obviously) and the ability to make use of the higher hypertransport (3600mhz for 95/9600vs 2000mhz for current x2's)
and it would be a significant performance loss if you were running applications that rely heavily on memory bandwidth. indeed.
not many of us here run said applications. as far as like, gaming...you're not going to see a difference i dont believe.