Asus EN7950GX2 - GeForce 7950 GX2
The Card Up Close
For the amount of available horsepower and on-board resources the Asus GeForce EN7950GX2 has to offer, its size is surprisingly compact. Even with two honkin' big GPUs and a full 1GB of RAM (512MB per PCB), the card doesn't expand beyond the dimension of a standard two-slot design. It's also actually significantly shorter than its predecessor, the GeForce 7900 GX2, an OEM only variant that never made it to the mainstream market.
The Asus EN7950GX2 employs a standard reference design from NVIDIA with no modifications whatsoever. The turbine fans used are relatively quiet and we didn't hear them spin up to any offensive level during our entire battery of extensive benchmark runs. The two PCBs with their high-end GPUs attached do get a bit warm though. Specifically we measured temps with an infrared thermometer gun at a couple of spots on the backside and front of the card and registered temps in the 160oF range, which is alarming to say the least. Never once did the card exhibit instability though, whether in single card SLI mode or Quad SLI with two cards baking in the system. Regardless, if you are considering any GeForce 7950 GX2 variant, from Asus or others, make sure you have adequate ventilation in your chassis to keep ambient air temps inside your case within reasonable limits.
The two circuit boards that comprise a single Asus EN7950GX2 are connected, as are all 7950GX2s with a tiny edge connector-style circuit board that routes signals sent from the NVIDIA PCI Express Switch that resides on the primary base card. The top GPU card plugs into the base card mezzanine style and the 48 lane PCI Express Switch allows for a full SLI configuration in a single X16 PEG slot on the motherboard. This NVIDIA PCIe Switch is not a trivial piece of silicon as it must perform high speed inter-GPU communications as a link back to the root CPU complex on the motherboard. These operations are extremely latency sensitive and NVIDIA's engineering prowess is to be applauded as the switch performs very well offering flawless, full SLI connectivity, which equates to a pair of X8 PCIe connections to each GPU and then aggregated back down to a single X16 connection in the PEG slot.