>>715209902nta but SLI is dead, and mutli gpu is only officially supported by Nvidia's workstation GPUs. I've seen a video of this dude somehow using Lossless Scalling to do the same thing, and even mix it with an AMD and Nvidia GPU, doesn't look ideal but it's cool to look at and could be a cool option for people on a budget and with a spare GPU.
https://youtu.be/PFebYAW6YsM