Compared to 2600k BD wins 2 out of 10 tests ( Winrar and Techarp x264 2nd pass )
Compared to 2500k BD wins 7 out of 10 tests ( wins are on throughput not single threadedaltough the Sandra tests on the 2500k look strange, you shouldn't have that difference vs. 2600k, HT doesn't matter )

Conclusion based on this sample test : 2500k < BD < 2600k overall, but in low threaded scenarios it doesn't hold a candle to both the 2500k and 2600k and losses even to the Thubans.

2nd conclusion : in Crysis, even with 2 6990 you're GPU bottleneck at 2560x1600. The I3 2100, 2500k, 2600k and OC FX flatten at around ~92 FPS. Obviously, their compute power is significantly different which can be seen in the lower resolution mode where GPUs aren't braking the system.