Review GeForce GTX 580 in 3-Way SLI: Is it Really That Good?

Conclusions

Slightly different compared to our previous GTX 580 SLI test, we didn’t see as much performance improvement by adding a third GTX 580 card. There are some limiting factors that eventually led to 3-way SLI’s less impressive performance scaling.

The first one is bandwidth limitation from the motherboard. Today’s motherboards have a maximum amount of 32 PCI-express lanes for data transfers between the chipset and the processor. Two graphics cards will have 16 PCI Express lanes assigned to each of them (x16, x16). A third card will split the bandwidth further so that the only the first card will have full, 16 PCI-express lanes while the second and third card would have to settle with 8 lanes each (x16, x8, x8).

Secondly, we noted a CPU limitation (“bottleneck”) in some of our games. Even our overclocked Core i7 is still too slow for the three GTX 580s. You will need the fastest processor available to maximize their performance.

Last but not least, there is the software limitation. In the case of 3-way SLI, not all games are able to properly recognize and put the third card to full use. You can see this in our Lost Planet, Resident Evil 5, and DiRT2 (non-surround) benchmark results, where 3-way SLI failed to give any performance improvement at all.

So, is it really that good, GeForce GTX 580 in 3-way SLI? If you are an avid overclocker whose goal in life is to score higher points in 3D Mark Vantage, the answer is yes. They will help you with the scores. As for casual or even hardcore gamers, a third GTX 580 is a rather pointless addition. Why? First, you won’t get a level of performance that is significantly higher than two GTX 580s in SLI. Secondly, the setup consumes way too much power for the amount of performance scaling it offers. We were surprised to learn that our 3-way SLI rig consumed some 906 watt of electricity. Show that number to a nature activists and he or she will accuse you of committing a crime against the environment. Finally, the cost is too high to justify the purchase. Rather than spending 500 bucks for a third GTX 580, it would be better if you use the money to buy some other gaming peripherals instead.