Comparing GeForce Models: 7900 GX2 And 7950 GX2
The GeForce 7950 might have a higher model number, but we would like to point out that this in no way means that there should be a performance increase. Obviously there are major physical differences in the board size and layout, but Nvidia has stated clearly that there are no major performance differences between the GeForce 7900 GX2 and the GeForce 7950 GX2.
Looking at the design, we can see that Nvidia is using the same PCIe switch on the bottom PCB, like the design of the GeForce 7900 GX2. However, instead of placing three risers to connect the top and bottom PCBs, there is a single long riser that runs through the middle of the card to allow better airflow by the fan on the lower PCB.
Another change by Nvidia was to move the DVI and VIVO ports from the bottom PCB to the top. This change makes it possible to exhaust the hot air from the lower card out the back of the case. The fan intake was moved to the far edge of the card to maximize the amount of air that the fan can draw.
Another innovation in the cooling design is the layout of the memory. Instead of arranging four pairs of two chips in a horseshoe pattern, Nvidia has put them in two blocks of four in an L-shaped pattern. This design puts the memory on the outer edges of the front board and towards the middle of the case. A single long section of the cooler covers the PCIe switch on the lower PCB.
We believe that these advances in layout can only enhance the airflow to all of the major components; it also encourages the expulsion of hot air from Nvidia GPUs out of the case. While the cooling solution on the GeForce 7900GTX forced some of the air out of the case, only half had the chance to leave, while the other half was directed back to the center of the enclosure.