This might be obvious but I couldnt tell by your picture with the lid reinstalled with the red rtv. There is a gap in the black rtv probably to keep pressure from building up under the lid.
I want to buy a 6950 but all of them say 2.1. My motherboard says 2.0. Will the 6950 work with my motherboard (gigabyte ep45-ud3). BTW, nvidia stuff says pci-e 2.0 so I may have to settle for a 560 ti.