TechPowerUp takes a look at the NVIDIA GeForce RTX 4090 PCI-Express Scaling
A quote from the article:
The new NVIDIA GeForce RTX 4090 is a graphics card powerhouse, but what happens when you run it on a PCI-Express 4.0 x8 bus? In our mini-review we've also tested various PCI-Express 3.0, 2.0 and 1.1 configs to get a feel for how FPS scales with bandwidth.NVIDIA GeForce RTX 4090 PCI-Express Scaling Review