The VRAD utility is another new benchmark to our test suite, courtesy of Valve. VRAD is one of the three major phases in compiling a level with the Hammer editor for Valve’s Source engine. The first stage called binary space partitioning divides the level up into a set of polygons that can be represented as a tree-like structure. The second stage calculates visibility information for polygons and light sources. VRAD is the last stage, where radiosity is calculated for the level based on the number and positions of various light sources. It is also the most taxing of the three stages in compiling a level – hence the most useful benchmark from the perspective of a game developer.
Figure 4 – VRAD Performance
VRAD has very modest performance gains with the newer generation processors. Harpertown’s IPC is ~5% higher than Clovertown, although it is unclear what precisely is responsible for this change.