[SOLVED] Second monitor increases power draw by 40W.

lekto · Last edited by lekto on Tue Dec 03, 2024 3:18 pm; edited 1 time in total

I have this PC:
CPU: Ryzen 9800X3D,
RAM: 64GB@6200MT/s DDR5,
MOBO: ASRock X870 Steel Legend WiFi,
NVME: 2x1TB Samsung,
OCZ 500W bronze PSU,
Wraith SPIRE from Ryzen 1600,
kernel: gentoo-sources-6.10.15.
Monitors: BenQ E2200HD and DML-419W210

On the login screen (SDDM), this PC draws about 60W, which sounds what I would expected. When I added Radeon RX 5700, power draw increased to about 80W, which also feels right. But, when I plugged in a second monitor power draw increased to about 120W. I read some time ago that plugging a second monitor in causes GPU to run it's memory at max speed and it will increase power draw, but paying 40W for the second monitor is ridiculous. Is there anything I could do about it? I have VAAPI acceleration in MPV, and played some games already, so GPU drivers are working.

lekto · Posted: Tue Dec 03, 2024 3:17 pm Post subject:

I plugged one of my monitors into the HDMI on the motherboard and it worked. I didn't notice much power draw increase; I tried fullscreen games on both monitors, and in both cases, games were rendered on the discreet GPU. Only downside is the second monitor shows garbage from a boot process until I log into desktop, but this maybe can be fixed with Plymouth.

zen_desu · Tux's lil' helper Joined: 25 Oct 2024 Posts: 140

sebas86 · Posted: Sun Dec 08, 2024 4:07 pm Post subject:

What kind of drivers are you using? Are they configured correctly?

It's possible to run AMD GPU and get working graphics interface with open source driver, but without properly configured 3d acceleration. In this case all tasks are handled only by CPU and even web browser or for example Spotify can cause very high CPU utilization and increased power draw. Please take a look on CPU utilization, maybe that is a source of the problem.
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lekto · Posted: Sun Jan 12, 2025 5:07 pm Post subject:

I compared it to my older PC, and the same effect occurred: power draw increases after plugging in the second monitor. During the holiday, I played some games and confirmed that the GPU is loaded.

Unfortunately, Plymouth doesn't run when both monitors are connected; I see black screens for a second and then back to the console, but the boot process is stuck because there is no password prompt. Plymouth runs correctly when only one GPU has a monitor connected, but not when both GPUs have monitors connected. Looks like I have to start thinking about an ultrawide monitor.

Ralphred · l33t Joined: 31 Dec 2013 Posts: 738