The present renaissance of multi-processor graphics hardware commenced back in 2004 when Nvidia announced its SLI technology that would allow using two cards as a single graphics subsystem. In its early days, the SLI platform had all manner of compatibility problems and depended wholly on the driver support for specific games, but all the issues were soon successfully solved and the technology won recognition among enthusiasts who are demanding the maximum possible performance from their computers.
The other leading GPU maker, ATI Technologies, responded to Nvidia with its CrossFire technology that had a number of differences from Nvidia’s SLI. Particularly, ATI’s solution used a hardware frame-compositing unit based on a programmable array Xilinx Spartan. As a result, graphics cards in a CrossFire tandem differed from each other: the Master card was equipped with a Compositing Engine and the Slave card lacked it. The technology was later modernized so that two identical cards could be used.
Still, there was one basic limitation with both ATI CrossFire and Nvidia SLI. You had to put two graphics card into your computer and so you needed a mainboard with two PCI Express x16 slots. Attempts were made to create graphics cards with two GPUs on one PCB that would occupy one PCI Express slot, but none of them, including the ASUS EN7800GT Dual, ever really took off, particularly because such cards, notwithstanding the single-PCB design, still required a SLI-supporting mainboard.
Announced in early June this year, the GeForce 7950 GX2 was Nvidia’s own attempt to create a dual-processor premium-class graphics card with unrivalled performance and without limitations on its use with different chipsets. Our tests showed that the attempt wasn’t entirely a success (for details see our article called Two for One: Nvidia's Dual-Chip GeForce 7950 GX2 Reviewed). The card indeed delivered superb performance in a majority of benchmarks we tried it in, but Nvidia hadn’t got rid of the compatibility issues completely. Despite the use of a special chip responsible for switching the PCI Express lanes, the new card wouldn’t launch on a number of mainboards. Particularly, it didn’t start up on our power consumption measuring testbed based around an Intel Desktop Board D925XCV. At the time of our writing our first review of the GeForce 7950 GX2, the list of compatible mainboards was only 39 names long.
Today, there are 64 entries there, 15 of which are ASUS’ products and 45 of which are mainboards based on Nvidia’s chipsets. In this review we’ll take a look at ASUS’ version of the GeForce 7950 GX2. It is called EN7950GX2/2PHT/1G. Let’s see if one of the major hardware manufacturers has got any surprises in store for us?