Half-Life 2: Lost Coast
This new expansion level for Half-Life 2 takes advantage of high-dynamic-range lighting, and it looks spectacular. HDR lighting requires the use of higher-color texture formats, so it really stresses a card's throughput.

The fireworks continue in the Source engine with HDR lighting. A single GTX 512 gives the GeForce 7800 GT SLI rig a run for its money, even. Quite likely, having 512MB of local memory onboard helps the GTX 512 here. The only other 512MB card in the bunch, though—the Radeon X1800 XT—trails even the 256MB GeForce 7800 GTX.