Tom Clancy: H.A.W.X.
Tom Clancy's H.A.W.X. (High Altitude Warfare eXperimental squadron) is an aerial warfare video game developed by Ubisoft Romania and published by Ubisoft for Microsoft Windows. It was released in United States on March 6, 2009 and features Microsoft DirectX 10.1 game play. For this game VSync was turned off, but Antialiasing was turned on and set to 4x for better image quality. 
All of the DirectX 10 options were set to high including Ambient occlusion (SSAO) on both the NVIDIA and ATI graphics cards. All of the ATI cards tested had DirectX 10.1 enabled.
Benchmark Results: ATI takes a beating here; the Sparkle GTX 275 outperforms the HD 4890 by 42 percent. The culprit, in this case, is anisotropic filtering: With AF set to "Use Application Settings," the 4890 scored 55 fps—slightly faster than the NVIDIA card's score with AF enabled. Similarly, the 4890X2's score dropped from 84 fps with AF off to 56 fps with AF on.
It wouldn't surprise me if there's a driver issue at work here, as the HD 4890 and the GTX 275 are typically much more competitive with each other. For now, however, I'd recommend turning AF off if you intend to play H.A.W.X. on an ATI card.
