VR Zone took a look at what's under the heatspreader of NVIDIA's GeForce 8800 graphics cards.
If you bothered to take a closer look, you may have noticed that the layer of thermal interface material is clearly visible. The IHS appears to be fixed with minimal mounting pressure. By removing this weak link, heat dissipation can be very much improved. I can imagine how much cooler the IHS-less GPU could possibly be.