SLI vs. CrossFire, Part 2 – High-end multi-GPU scaling

Left 4 Dead

Left 4 Dead (L4D) is a 2008 co-op first-person shooter that was developed by Turtle Rock Studios and purchased by Valve Corporation during its development. Left 4 Dead uses Valve’s proprietary Source engine.  L4D is set in the aftermath of a worldwide pandemic which pits its four protagonists against hordes of the infected zombies.

There are four game modes: a single-player mode in which your allies are controlled by AI; a four-player, co-op campaign mode; an eight-player online versus mode; and a four-player survival mode. In all modes, an artificial intelligence (AI), dubbed the “Director”, controls pacing and spawns, to create a more dynamic experience with increased replay value. It is best as a multiplayer game played against humans.

There is no built-in benchmark, so we created our own custom time demo which is very repeatable. The game is updated regularly by Steam and we chose the highest detail settings and 8xAA. We will save our comments until after we present both charts. First we test at 1920×1200 and 2560×1600 resolutions:

Again, we see significant improvement in framerates from dropping from 2560×1600 to 1920×1200 with our single-GPU cards but relatively less gain with multi-GPU which might indicate that our i7-920 might benefit from further overclocking – although it is unnecessary. We do see good scaling with both CrossFire and SLI.

On to our next chart at 5760×1080:

All of our video cards can play this game fully maxed out plus 8xAA and left 4 Dead would be an excellent candidate for playing in 3D Vision Surround fully maxed out.  And this time scaling returns to normal in relation to our CPU as our graphics system is more challenged by the increased resolution.