I've recently upgraded from an RX570 to an RX 5600xt and I've noticed that my GPU usage in-game (Fortnite, COD Cold War, WoW, etc) hovers around 60-70% with CPU usage roughly the same as well, so no apparent CPU bottleneck. Along with the low usage %, the GPU power tends to be about 65-80w at any given point. And here's the kicker, the GPU usage in benchmark testing (i.e. Time Spy, Fire Strike, Heaven, etc) seems to be right in-line with what I would expect, coming in at 97-99% usage.
Why am I experiencing lower than expected GPU usage in-game & about half of the MSI rated TDP but not during benchmark testing? vsync in-game is turned Off, run all games in Full Screen mode, & no in-game frame cap limit set.
CPU - Ryzen 5 1600 @ 3.7Ghz|RAM - 2 x 8GB Team T-Force 3000Mhz|Motherboard - MSI B350M Gaming Pro|PSU - EVGA 450BR