I switched from Windows to Fedora last week and I'm monitoring the stats with Mangohud when playing games. I used to run HWinfo on 2nd monitor when using Windows 11.

I have 6800X ( default voltage) . The card maintains higher clocks at lower power most of the time. I've set the same OC as on Windows with a 2700MHz max clock and in games I'm sitting pinned at 2670MHz-2700MHz almost all the time in Linux when I don't hit power limit (312W) while on Windows the actual clock barely went over 2600MHz and card was almost always bouncing off of power limit resulting in massive clock drops to 2300-2400MHz. On Linux the drops go down just by like 100MHz-130MHz at most in the same scenarios.

Unfortunately I'd need to install Windows again and do proper testing to compare but I wonder if anyone else can confirm/deny this to me.

At least on idle I can confirm for a fact that the card uses less power, usually around 30-35W while on W11 was like 40-50W.