What happened to SLI GPUs?

Those who have been into PC gaming for a while will remember than a few years ago, the absolute top-tier PC builders all had multiple GPUs in their PCs - up to 4 of them some times.

It was truly the pinnacle of excess, but why does everyone only have a single GPU these days? Well, it's because NVIDIA SLI is no longer with us.

A little background on what Scalable Link Interface (SLI) technology was, originally developed by 3DFX and then by NVIDIA after the acquisition of 3DFX. It allows 2 or more graphics cards to be physically linked to produce a single video output.

SLI was a parallel processing algorithm designed to increase the graphics computing power available.

The very first iteration was presented by 3DFX in 1998 with the Voodoo2 under the name Scan-Line Interleave, it was abandoned before being reborn in 2004 under the lead of NVIDIA, this time under the name SLI and redesigned to adapt to the PCI Express bus.

Bi-GPU graphics cards such as the GTX 295 used this technology to sandwich 2 GPUs around a single cooling block, but required a single PCIe slot.

From 1 January 2021, it was announced that this technology will continue to be supported by RTX 2000 and older cards, but SLI profiles will no longer be updated, meaning that newer games/applications will no longer benefit from these capabilities.

And the removal of Nvlink, the connection that enables SLI, came to an end with the launch of the RTX 4000 series.

So it's not really surprising that NVIDIA's engineers have decided to sacrifice the NVLink connector in order to reallocate die space to "integrate as much AI processing as possible" to improve DLSS performance.