I did a test with a power meter for my desktop PC (7700k at 4.9 GHz):
EnOS (KDE) idle after boot - 55W
Windows 10 “idle” after boot - 190W (!)
Note that I did wait for Windows to calm down after booting up, it took a while going down from 220W to 190W where it seems to have stabilized. Now I’m back in EnOS and with Brave open (60 open tabs) the system consumes 62W
Is it normal for Windows to have such much crap running while “idle”? I only use it for gaming but closed down all apps like Steam / Geforce Experience / Windows Update etc for this test. Besides this, a clean W10 install.
That looks more like GPU is drawing all the power. 7700k is rated around 90W. Or did you mess with overclocking under windows that somehow stuck the CPU in permanent turbo state? It may be disabled under linux.
What is the temperature on the CPU and is the CPU fan running at higher speed (noise) compared to linux boot? This double power should go somewhere and the generated heat should be visible.
Found the issue! It was the 3090 joyfully consuming 110W of power just displaying the Windows desktop… After installing the newest driver using Geforce Experience (with option “clean install” to reset nVidia settings to default), it dropped to 15W in idle. Total power in Windows is now a more acceptable 80W. This is also in alignment what “nvtop” reports (15-25W):
By the way, the reason I checked the the total power draw of the machine is that I’m about to upgrade from the 7700k (OC to 4.9 GHz) to a Ryzen 5900x. Max power draw today is about 480W-500W and I have a 750W PSU (older Corsair AX750). I wonder how much this will increase with the 5900x and if the PSU will manage…
Just goes to show you what crappy drivers do. The 5900X is 105W like my 3800X i think. I guess you are planning on pairing it up with the 3090. I still think you’ll be fine with the 750 watt. Processor is only 14 watt difference.
The Ryzen should be somewhat more demanding. Personally I would be fine with the 750 Watt PSU.
There are calculators like https://www.bequiet.com/en/psucalculator but depending on the source they may have an interest to up-sell you (OMG the theoretically spike max. draw, buy our amazing 1k Watt PSU). I would go there, check my current system against what they say and put that into relation with the new parts.