Actually TilDeath, different games place different demands on video cards. Aces High II is fill-rate limited, where the performance of the game is directly tied to the fill-rate of the video card.
Other games performance may be tied to shader performance.
Other games may be tied to triangle perforamance.
Memory performance, of a video card, will have an effect in Aces High II as well.
All that said, Aces High II is also very CPU dependent due to the flight model calculations. If the CPU is not fast enough, the performance of the video card will have little to no impact on the game performance.
I am not big on 3DMark as a test of a system due to how it leverages the systems resources. It is more video card intensive than CPU intensive. For what it is, it is fine, but it really will not give you a measurement of how Aces High II would run on a computer, given its focus on the video card, over the CPU.
As a matter of fact, of Aces High II is your primary game, 3DMark could actually lead you to build the wrong system. Aces High II leans more on the CPU than the video card due to the physics calculations being done.
Just FYI.
Back to the discussion, ATI Tray Tools is far better tool for ATI cards than RivaTuner is. As with any utility in the freeware category, I am concerned about how much longer it will continue to be supported. He used to hae a new version within weeks of a new ATI card family being available, but that has seemed to slow.