If it sounds like I’m not answering the question, sorry; finding out if Source (and Source 2) supports multi-GPU setups (like SLI) is not the easiest feat, but as far as I can tell, Half-Life: Alyx most likely doesn’t support it.

Does anything support SLI?

There are a lot of games that technically support SLI. Besides, almost any AAA released in the last decade will probably slap on the SLI support label. However, there are several issues that have arisen with some of these titles.

Does SLI improve graphics?

SLI helps you achieve slicker, smoother, more altogether mind-boggling graphics in your gaming. It’s a technology that allows you to use two or more video cards in the same set-up, using their potential as an aggregated whole, rather than just letting them each act to the maximum of their own performance.

Is SLI required for dual GPU?

To use dual graphics cards, your computer needs AMD or Nvidia technology that links the cards to produce a single output. The AMD graphics solution is called CrossFire and the Nvidia solution is named SLI. Finally, the SLI or Crossfire feature must be enabled in the GPU driver control panel.

Is CrossFire better than SLI?

For this reason, CrossFire enabled motherboards are more readily available and at a much lower cost. Another difference is that CrossFire only works in fullscreen mode unless engineered by developers to do so, while SLI is more flexible with compatibility in windowed/borderless mode.

Does SLI double performance?

SLI/Crossfire scaling is not 100%, so you won’t double the performance (this depends on the game and rest of your hardware aswell, check google for SLI tests). Also you are still limited by the RAM on single GPU since both cards need to store all the data.

Why is SLI bad?

SLI/Crossfire has a major obstacle: game implementation. If a game do not support multi-GPU (mGPU) properly, then running GPUs in SLI will not yield any increases in framerates, in some cases it can even DECREASE it.