1680x1050 High Performance
Dropping the visual preset to high at 1680x1050 meant that all tested graphics cards were able to deliver a minimum frame rate of at least 30fps. Even the $80 Radeon HD 5570 delivered with an average of 38fps.
Other graphics cards that we consider to be slow for gaming, such as the Radeon HD 5670 and GeForce GT 240, were more than capable of delivering playable performance at this resolution. Essentially anything equal to or greater than the Radeon HD 4870 is overkill at 1680x1050 when using the high quality visual settings.