TL;DR: NVIDIA's RTX 5090 graphics card requires 4 x 8-pin connectors for 600W power officially, but can operate with 3 x 8-pin connectors at 450W, seemingly running only 5% slower in 4K benchmarks.
Nvidia’s GeForce RTX 40-series graphics cards were the first mainstream products to feature the 16-pin power connector. However, Nvidia might not stick to this format for the upcoming GeForce RTX 4070 ...