Scalable Link Interface

Scalable Link Interface (SLI) is the brand name for a now discontinued multi-GPU technology developed by Nvidia for linking two or more video cards together to produce a single output. The technology was invented and developed by 3dfx and later purchased by Nvidia during the acquisition of the company. SLI is a parallel processing algorithm for computer graphics, meant to increase the available processing power.

The initialism SLI was first used by 3dfx for Scan-Line Interleave, which was introduced to the consumer market in 1998 and used in the Voodoo2 line of video cards. Nvidia acquired the technology when it bought out 3dfx, but never used it. Nvidia later reintroduced the SLI name in 2004 and intended for it to be used in modern computer systems based on the PCI Express (PCIe) bus; however, the technology behind the name SLI has changed dramatically.