Beyond3D taking a look at NVIDIA’s Pre-Christmas high end booster with the GeForce 6800 GTX 512MB.

The most notable difference with the new 512MB board is obviously the cooling solution. The fact that NVIDIA used a single height cooler on the original GTX was an indication that there may still be more performance in the core, had it been cooled more aggressively, and that's the case with the
new 512MB board, moving to a double height cooler solution. The cooling relies on a large fan in the centre of the board sucking air up and pushing it either side so that its partially vented out the back of the case and partially, internally, towards the front.

GeForce 7800 GTC 512MB Review