Let's keep this thread on track, the question is around ISO 1600. The 7D gets better higher up the register it goes, and we can open up yet another thread on the 7D and how it requires faster shutter speeds and better glass if you want to tightly crop or 100% pixel peep. For some, the extra work and changes in their shooting habits and changes to their glass just aren't worth it, and it is better to move to a different body.
If we shoot the same lens in a dark setting on both the 7D and 5D2, ignoring the differences in DOF but keep all other settings the same (otherwise the 5D2 would have to shoot at ISO 3200 to the 7Ds 1600), here are the results. The 7D focused very well in the dark setting, the 5D2 took a couple of presses. I have MFA's this lens to each body, but I might have to do it again on the 5D2 it seems. In any case, you can see the difference in noise, mostly luminescent noise.
First is obviously the 7D...



