Nvidia’s earlier 7950 GX2

Unlike AMD and the legendary 3dfx, NVIDIA is faithful to the trend it started with the GeForce 7950 GX2 and uses two PCBs on the GeForce 9800 GX2, even if photos of the board don’t show this fact, due to the cooling system cover. Dual PCBs have their advantages, the first being easier wiring of the memory chips. Numbers favor NVIDIA as the manufacturer was able to maintain a 1 GHz clock (970 MHz for the 8800 GTS 512 MB) when AMD had to content itself with 900 MHz on its Radeon HD 3870 X2 built using one PCB. That’s even lower when compared to the 1125 MHz of a single Radeon 9870.

Unlike the 7950 GX2, the 9800 GX2’s two PCBs face each other and transmit heat to the same heat sink, which is cooled by a single fan. If this approach increases cooling constraints (both GPUs are close and a single heat sink must dissipate the accumulated heat), there are no significant temperature gaps between the GPUs (a problem partially solved on the 3870 X2 thanks to the heat sinks). The small amount of heat transmitted by the GPU to the PCB is also better spread since there are two of them.

Unfortunately, NVIDIA was unable to put all components on a shorter card. The 9800 G2X’s length of 26.7 cm is typical of a high end card (8800 GTX, Ultra and 3870 X2). Likewise, two power connectors (6 pins + 8 pins) are still necessary and finally, only a fraction of the heat is sent outside the case. Most heat is sent to the top of the card and is therefore is recycled in the case, the grid on the brace being too small because of the number of outputs.