After nVidia bought 3Dfx, Multi-GPU Systems were dead for several years until nVidia came up with this idea again in 2004. As nVidia had bought all technologies and market names from 3Dfx, too, they simply used the name SLi again. Today’s SLi works with up to three video cards, which is called 3-way-SLi. There were also attempts with four cards, but this failed due to limitations in the DirectX9 API. Today’s DirectX10 API however would support this.