I was surprised to see any performance gains at all when comparing the Intel Core i7 980X Extreme to the Core i7 975 EE processor here. However, the larger L3 cache does appear to provide a small performance advantage in UT 3. The Core i7 Extreme was also a full 33fps faster than the Core i7 950 at 1024x768 and 36fps compared to the Core i7 920.
A slight performance advantage over the Core i7 975 EE is also seen when running Company of Heroes Opposing Fronts, just enough for two or three extra frames per second at both resolutions tested. The Core i7 980X Extreme Edition was also about 13fps faster than the Core i7 950 and 30fps faster than the Core i7 920 at 1024x768, but not so much so when compared to either processor at 1920x1200.
In Far Cry 2 the Core i7 980X was just 4fps faster than the Core i7 975 EE at 1024x768, and as much as 18fps faster than the Core i7 920 processor at this same resolution. Compared to the Core i7 950 it was around 10fps faster. Again all three were pretty close at 1920x1200, however, which means at this resolution the GPU is the bottleneck.