The first thing is the actual size of the card. While the GeForce 7900GX2 was very long, the 7950GX2 is about the size of a 7900GTX in length. The card should now fit into normal ATX cases with no problem. The GPU cooler has become much smaller, but still covers the memory chips as well. While the 7900GX2 had two SLI connectors, the GeForce 7950GX2 only has one, located in the middle of the card. There will be no problems using the card by itself, or using two of these in SLI. While QuadSLI with 7950GX2 will not be supported at launch, it will be in the future.
Here you see the card inserted in an Intel mainboard with a single PCIe x16 slot, while the second picture shows an AMD based board, with two of these cards installed. Note the single SLI bridge used. Using a bigger PCI card right under the graphic card will not block the GPU cooler anymore, as was the case with the 7900GTX.
Lets take a look at the specifications.