Quote Originally Posted by Charge
Yes it is, more memory could be even slower, but depends on your resolution.
No it isn't, the 8800GT almost reaches the 8800GTX in speed while the 8600GT is significantly slower. More memory doesn't make a slow card any faster. Doesn't mean the 8600GT is a slow card, but definitely not as fast as the 8800GT.

Here's a chart for you, not ideal as the 8800GT is overclocked etc but it may give you a rough idea about how powerful the cards are.