PCI-Express has been the standard for connecting video cards and other expansion devices inside of computers for many years now, and several generations of the technology have now passed. With each of those generations, the amount of data that can be transferred over the PCIe connection has increased. How much impact does that have on modern video cards? Is there any benefit to running a PCIe 3.0 card in a 4.0 slot, or loss if using a 4.0 card in a 3.0 slot?
NVIDIA's new GeForce RTX 3090 24GB is an incredibly powerful GPU, but the power consumption makes it difficult to use even two cards in a desktop workstation. Are three or even four GPUs possible, or is the heat and power draw too high to be feasible?