Using multiple GPUs inside a PC dates all the way back to the early 2010s when more demanding programs began showing up. Those of us who built or upgraded systems back then had our fair share of experiences with dual GPU configurations, complete with groundbreaking technologies like SLI and CrossFire that paved their way, but the GPU landscape has changed for the better with newer and more powerful solutions.
Neither SLI nor CrossFire tech exists right now, meaning the experience of using a multi-GPU system isn't as seamless as it used to be. The lack of these technologies also means that newergraphics cards installed on your computer can't share any resources either. So, while you cantechnically use two graphics cards on a PC, the process of setting up such a system is very demanding and isn't very practical due to limitations on both hardware and software fronts, especially if you want to use both GPUs simultaneously.
Are Nvidia SLI and AMD CrossFire dead?
Nvidia ceased SLI driver support in 2021, but it's been on life support since 2016, when it was limited to just GTX 1070, 1080, and 1080 Ti GPUs, and its support was reduced from four graphics cards down to two. The GeForce RTX 3090 was the only RTX 30-series GPU to support SLI, and none of the modern RTX 40-series graphics cards support it.
As far as CrossFire is concerned, the AMD RX Vega was the last AMD GPU to support it. The company has since stopped making drivers with per-game CrossFire support, meaning you can no longer use it practically to set up a multi-GPU system using AMD GPUs.
SLI and CrossFire were never great
You may have seen people in the community use multi-GPU systems in the past, but they were never practical to begin with. Yes, this tech allowed users to use multiple GPUs simultaneously while sharing resources, but building a system that shared resources within demanding tasks like games has mostly been janky. There are plenty of forum posts and discussions out there on the rather complex nature of this tech. It also meant you were sacrificing efficiency for some additional frames.
Can you use multiple discrete GPUs simultaneously?
Yes, but not without technical difficulties
Yes, you can have two or more fully functioning graphics cards installed on your computer, provided your motherboard has enough PCIe slots and your power supply is powerful enough, but don't expect them to share resources or even run simultaneously on the same app. Using two discrete GPUs is more complicated than you think, especially if they come from different manufacturers since they can't utilize the same drivers and may even have trouble getting recognized by the operating system. All this results in various technical difficulties and is often not worth the hassle. It's good for those who want to try and experiment with something new like the folks over atQuasarZone recently did, but it's far from a practical solution.
Can you use a discrete and integrated GPU at the same time?
Useful in some cases
You can theoretically use your discrete andintegrated GPU simultaneously, but no applications or software offer support. One of the ways you can utilize the iGPU along with a discrete graphics card is by using Intel's Quick Sync technology that offloads certain footage encoding/decoding on the iGPU. That's great for those using, say, Premiere Pro for editing, in which the integrated graphics of your processor can take over things like live footage scrubbing, lowering render times, and more if/when your discrete graphics are already maxed out.
Closing thoughts
There is a reason why multi-GPU systems are no longer popular.Multi-GPU gaming is no longer a thing, meaning you'll only find them used for GPU rendering and machine learning tasks. But even those systems are quite rare, as using anything more than a single discrete GPU on a modern computer results in various stability and other performance issues. You are better off buying one of the modern and powerful GPUs out there instead of setting up a useful multi-GPU system in 2023.
