The Far Cry 2 Benchmark Tool was run at a 1920x1080 resolution on the "Ranch Long" map at "Very High" graphics detail and no anti-aliasing or Vsync. 3 runs were performed, and the average of the three runs is reported.
As the processor frequency (alongside its respective architecture) determines its performance, it's of no surprise that performance was the same whether undervolted or not, as long as you're not starving the processor of needed power and introducing instability. As most games are now coded to take advantage of multiple cores, many times it matters more the number of cores your computer has, and less on how fast the processor operates. Obviously there are exceptions, but popular games such as Battlefield 3 have become increasingly graphics processing-dependent, and less reliant on the processor in your rig. However, in Far Cry 2, performance was still boosted by a non-negligible ~5.5% in both DirectX 9 and DirectX 10 performance.
PCMark7 Professional includes a full array of real-world system metrics, and we ran the "Computational" benchmarks to measure our processor performance. In the raw computational performance tests, the i5-2500's score scales linearly with clock speed, and overall we see very good scores from the chip. With each .5GHz (15% of stock speeds) increase in clock speed from the 2.8GHz underclock (stock speed for the i5-2300), we see a 13.3% increase in our computational score.