Left 4 Dead
We tested Valve's zombie shooter using a custom-recorded timedemo from the game's first campaign. We maxed out all of the game's quality options and used 4X multisampled antialiasing in combination with 16X anisotropic texture filtering.

You just can't stress either of these cards terribly much with Left 4 Dead and these (pretty darned high) quality settings. They just offer more GPU than one needs for this game. Once again, though, the 4890 OC is faster in the two lower resolutions before falling behind at 2560x1600.