SLI v. CrossFire
Sunday, April 18, 2010 
A Quad SLI motherboard with cards installed. Image courtesy of techPowerUp.com. Multiple video cards can be installed in a single computer to improve graphics performance. If 2 to 4 PCI Express graphics cards are bridged, they can increase effective video processing power by rendering frames in parallel. Nvidia’s multi-GPU technology is called SLI, for scalable link interface. CrossFire, (or ‘CrossFireX’, for the current generation), is ATI’s solution.
CrossFire can be implemented with different GPUs from the same family; SLI requires the use of 2 cards with identical GPUs. Because it’s possible for one card to be faster than the other in a CrossFire installation, ATI created several video rendering modes that balance the load, assigning more work to the faster card.
In order to implement SLI, a motherboard based on Nvidia’s nForce chipset must be used; some Intel chipsets are also supported. ATI is a subsidiary of AMD, and most AMD chipsets support CrossFire. The CrossFire architecture can be enabled on many Intel chipsets as well.