Up to this point in time, though it will be different with the next generation of mid-range video cards, the big difference between mid-range video cards and upper-end video cards is how they perform when running AA. Keep in mind that though both of these cards are priced in the economy range, the 9600GT is a mid card, and the 9800GT is a lower level upper-end card, though I found in earlier testing that the 9600GT actually performed ok running AA, probably the first mid-range card to do so.
Company of Heroes: Opposing Fronts
Opposing Fronts did not begin life as a DX10 game, it received that capability in a patch. It really doesn't act like a DX10 game though, it isn't as hard on video cards as most other DX10 games. I used the onboard performance test, settings were: High, AA x 2, 1680 x 1050.
As expected, AA made the 9600GT struggle some. Actually, the game was still playable though.
PT Boats - Knights of the Sea
PT Boats is a water-based game with some great graphics, though it looks much better with AA than without. I used the standalone demo benchmark, settings were: DX10, Medium, AA x 2, 1680 x 1050.
Though the 9600GTs performance went well, the main difference between the two was the minimum FPS, some drastic camera angle changes in the video really slowed down the 9600GT, but affected the 9800GT very little.
Crysis is my favorite benchmark for several reasons, mainly is that it is system hog, and really stresses a CPU, memory, and GPU. It can bring an otherwise great system to its knees. Most modern video cards will run it ok, but when you add AA, you really separate the men from the boys.or the upper-end from the mid-range. I used the Crysis Benchmark Test by MadBoris Vergiza, settings were Medium, DX10, GPU, AA x 2, 1680 x 1050.
As I expected, here is where the 9600GT really struggled. It really wasn't playable here, but the 9800GT did just fine. Adding AA caused the 9600GT to drop about 15FPS, only about 7FPS with the 9800GT.
I tried some older games, including F.E.A.R. and Supreme Commander. As was expected, the 9800GT performed 15%-20% better than the 9600GT, about halfway between it and the 9800GTX. I really saw no need in posting the scores, all were well over 50FPS.