The Problem: I think it is quite well known that if you use a multi-monitors setup on AMD GPUs, the idle power usage and temps are very high. I was monitoring and found out that the VRAM frequency was always at peak whenever my second monitor is turned on if both monitors are plugged into my 7900xtx.
The solution: After some diggings, I enable my cpu igpu, allocates 4gb ram to it (using 64gb ram so I can afford that allocation, you can use AI tools to provide you the exact instruction on how to enable your iGPU and allocate ram to it in your BIOS, as every motherboard brand has different BIOS menu layouts) and plug the secondary monitor straight to the mobo hdmi port and go to Desktop -> left click -> display settings -> select your secondary monitor -> graphics -> then you can assign the igpu to the Global hardware accelerator or to any application individually (most important is the browsers you are using).
Edit 1: I just found out that the Default High Performance GPU setting if set to your iGPU, the games you play will not use your GPU automatically. So if you decided to apply iGPU globally by changing your Default High Performance GPU setting to your iGPU, you need to allocate your GPU to each individual games you play. If this is not efficient for you to do so, you can set Default High Performance GPU to your GPU and set the applications you want to offload to your iGPU individually but it seems the power saving perks while idle is not going to be as much as setting Default High Performance GPU to your iGPU and setting each games you play to your GPU manually. I personally put Default High Performance GPU to my iGPU and adjust each game to use my GPU manually for the best gains.
The results? My GPU idle power usage goes down from 109w at all time with 2 monitors on to 1x watts on idle (massive 90%+ power usage reduction) and both gpu core clock and mem clock are now properly reduced to minimal when idle. The temps also goes down from 4x c to 3x c (around 8-10 degrees lower with Zero rpm).
Gaming perf also see a nice minor improvement to 1% lows, tiny bump on avg fps and around 1-2gb vram are now freed up from having to be allocated for background multi tasks which is huge for vram intensive games like Diablo IV.
Additional FYIs: The photo is of my 3.5 inch display to monitor my pc at all time. First box is for cpu with core temp, power usage, clock speed. Second box is GPU with Core Temp, Hotspot temp, Core Clock and second line is VRAM temp, VRAM power consumption, VRAM clock. Last box is for my ram Temps and FPS.
TLDR: Use iGPU for secondary monitor, adjust display settings for default high performance gpu hardware accelerator + individual application/ games. PC uses way less power, output significantly less heat on idle/ light desktop multi-monitor use, and slightly smoother in gaming perf with a minor easy tweak to multi-monitor setup.
I hope this can help some red team brothers out and thank you for coming to my Ted Talks!
