It might seem like graphics cards of today are veritable power houses compared to their predecessors, offering not only much greater performance, but demanding much more power in the process. And you're right, they are, with the RTX 3090 demanding as much as 350W from your PSU and cooler. But That's nothing compared to what cards of the future may need. A new specification for a PCIExpress 5.0 power connector suggests some GPUs could be able to pull as much as 600W from a single cable.
This may seem absurdly unnecessary, but does open up some interesting potential for future high-end cards, and may make for more streamlined GPU cabling at the lower end. An RTX 3090 Ti specification recently suggested it could have a TDP of 450W, so we're not a million miles from these sorts of demands. Making sure it can do so from just a single cable is a lot easier than having two or three cables doing the same job.
The new PCE 5.0 cable will be a 12-pin affair, like a chunkier version of the bespoke solution Nvidia used on its RTX 3000 series graphics cards. When you combine the 600W potential of that cable with the 75W that PCIExpress slots on the motherboard can deliver, you have the potential for 675W graphics cards with just a single chunky cable hooked up to them.
That's way better than multiple 8pin cables, and means we could see some supremely power hungry cards in the future. Cooling would be an interesting problem at that sort of level, and unless you have A/C in your room, it's going to feel like having a space heater on all the time. That's no fun in summer.
Still, the performance could be exciting. Watch this space for the next-generation GPU launches in 2022.