Multi-GPU: Problems and Limitations

When we tested systems with a single dual-chip graphics cards, we didn't face any serious problems. Both: ATI Radeon HD 3870 X2 as well as the new Nvidia GeForce 9800 GX2 worked fine, except for the standard issue of all homogeneous dual-chip graphics solutions ¨C no performance improvement in games that do not support multi-GPU in the drivers on the software level.

However, we had the whole bunch of issues pointed out for ATI CrossFireX and 4-way SLI systems. Among them are the following ones:

• Overall instability of multi-chip configurations that leads to system freezing, improper enabling of the CrossFireX/Quad SLI modes and random performance hits.
• Spontaneous freezing of Nvidia GeForce 9800 GX2 Quad SLI configuration in 3D applications.
• Freezing and unstable operation of Nvidia GeForce 9800 GX2 Quad SLI in Crysis and inability to run in 2560x1600 resolution.
• Unstable operation of Nvidia GeForce 9800 GX2 Quad SLI in Enemy Territory: Quake Wars with random return to desktop during resolution change.
• Screen flickering in Hellgate: London on Nvidia GeForce 9800 GX2 Quad SLI.
• Unstable enabling of CrossFireX mode in case of two ATI Radeon HD 3870 X2 cards.
• No support for triple- and quad-processor configuration with ATI CrossFireX in OpenGL applications.

Besides, we have witnessed Nvidia 4-way SLI and ATI 4-way CrossFireX systems overheat multiple times, so it is not only the drivers that should be blamed for unstable operation.

As you see, the performance of contemporary multi-processor graphics systems in the consumer segment is still far from ideal. The developers managed to achieve acceptable stability for dual-chip configurations, but in case of more than two graphics cores the situation leaves much to be desired. These systems suffer not only from performance and compatibility issues but also have a lot of stability problems. At this time, they are mostly an expensive toy for computer enthusiasts with unlimited budget who love playing with computer hardware, rather than stable and reliable elite gaming platform for everyday gaming fun.