Game developer Valve launched their Source Engine with Half-Life 2. HL2 is a game that offloads some of the work to the CPU, so it is a good test for the latest graphics cards as well as overall system performance but will bottleneck if the processor and bus are too slow for the graphics card. High Dynamic Range lighting was later added to Half-Life 2 and the Source Engine during an update from Valve Software. We use a custom timedemo for our testing, DP_Coast_01.dem.

Something interesting happened in the 1024 x 768 test. The scores were close together due to CPU limitations but both of the ATI cards were able to score higher frame rates than what the 7800 GT could achieve. When we move to a resolution of 1600 x 1200, the traditional pattern takes shape only with the GTO / XL ATI R430 equipped card beating out the NVIDIA GeForce 7800 GT.