Quad SLI May Increase Performance, But May Degrade Too – Tech Preview

by Anton Shilov

[ 04/17/2006 | 04:13 PM ]

Nvidia’s multi-GPU technology has come a long way and is currently featured in numerous systems designed for performance-minded enthusiasts. However, the introduction of ATI CrossFire multi-GPU platform allowed ATI to return to the ultra-performance space with quite a decent offering. But Nvidia still wants to be one step ahead and its quad SLI multi-GPU technology is just a yet another proof for that. 

MVKTech web-site has managed to lay its hands on two GeForce 7900 GX2 graphics cards that feature two GeForce 7900 graphics chips per unit, benchmark them in several popular benchmarks, overclock them, analyze how those dual-PCB graphics boards work and also write some thoughts about owning ultra-high performance system featuring Nvidia quad SLI technology. 

Each GeForce 7900 GX2 graphics card has two GeForce 7900-series graphics processors clocked at 500MHz and is equipped with 1GB of 1200MHz GDDR3 memory in total (512MB of memory with 256-bit access per chip). Two of such graphics cards enable quad SLI systems. 

Performance tests run by the web-site show that the biggest gain the 4-way SLI has over 2-way SLI is in case of the 3DMark03 benchmark – about 20% (34640 versus 29 001), a slight performance increase of 7% (8492 vs. 7924) was observed in 3DMark06, whereas in the 3DMark05 performance actually degraded by 1% (12 797 versus 12915) on 4-way SLI compared to 2-way SLI. The testbed used for experiments was based on AMD Athlon 64 FX-60 microprocessor and was equipped with 1GB of memory.

X-bit labs managed to get 14 344 points in 3DMark05 and 8917 points in 3DMark06 benchmarks using Radeon X1900 XT CrossFire tandem and AMD Athlon 64 FX-60 chip.

MVKTech has also managed to run some benchmarks in 2560x1600 resolution, the setting recommended by Nvidia for quad SLI game-play, while in some cases 4-GPU system was considerably faster compared to dual-GeForce 7900 GTX setup, in other it was just on par or even behind, which may indicate that there are still some driver issues with the technology.

Systems with quad SLI allow to turn on 32x antialiasing, the maximum level possible today, or to play the latest games in 2560x1600 resolution with all the quality improvement features activated. According to benchmark results obtained by MVKTech, four GeForce 7900 graphics processors may not only provide only slight performance advantages over two of such chips, but may even degrade performance, unless eye-candy settings are activated. 

• MVKTech: Nvidia GeForce 7900 GX2 1GB Quad SLI.