In my current PC I have a PNY 8600 GTS 256Mb DDR 3 card. A friend of mine has a Hd3650 512Mb DDR3 card that he is going to replace and has offered it to me. I've had a look on the net and Tom's and can't seem to find any info which tells me which is better.
My max res is going to be 1366 x 768 as I have a 32" 720p T.V. which I use as a monitor. The PC is used for media centre, video editing and games.
Stuff in the Chart is generalized.
The person maintains it says that in general until you get 2-3 levels different, you will not feel a big difference in real world use.
If you note, you 8600GTS is one level higher than the 3860.
As a result, you may have a slightly better card or its a wash.
As Hallow pointed out, the 512mb of memory does not really help cards around that performance level. The reason is they are not powerful enough to run resolutions and color depths that would need that much ram.
The extra RAM is usually just for marketing.
i have two computers
-intel core 2 duo 2.33ghz with sapphire HD 3650 256ddr3 128bit pcie
-amd x2 2.7ghz with msi nx 8600gts 256 ddr 128bit pcie
in Cod 2, 4, 5, race driver GRID, crisys, unreal 2004, 8600gts is much better then hd3650
in unreal (1680-1050 everything full ) 8600gts work perfect
the big difference is in GRID
(sorry for my english )