Random question re power draw from 2nd monitor

Double07 · 21 Oct 2020 at 18:17

Wondered if anyone might have some insight into this as it does seem a little odd!

I have 2 monitor plugged into a 1080Ti. One is a G-MASTER GB3461WQSU-B1 (3440x1440) and the other is a AOC Q3279VWFD (2560x1440). When I look at HWInfo with just the 34UW it shows as the GPU consuming around 20W when idle, however if I have the 2nd display enabled as an extended display the GPU power draw jumps to around 70W when at idle.

The 34UW is connected by DP and the AOC by HDMI, but the massive jump in GPU power draw at idle doesn't really seem consistent with what I would expect. Does anyone have any ideas why this rather pronounced jump in GPU power draw would occur simply by enabling the 2nd monitor? The system is completely at idle, nothing running in the background that shouldn't be, just a massive spike as soon as I enable the 2nd monitor.

**EDIT** If I run either of the monitors as a single display the GPU draw is around the 20W mark, if I run the two displays as duplicates then this increases by a couple of W, nothing more. As soon as I select extend the displays it skyrockets.**

Hopefully someone might have some insight!

Cheers

Double07 · 21 Oct 2020 at 19:49

Yeah I get what you are saying but the primary display is a much higher resolution, around a 35% higher pixel count. It just seems a huge difference in GPU power draw for the second screen when its doing nothing at all other than idling(I am comparing complete idle power draw figures here). I get it might well just be a fact of life but I have never noticed it before so was looking foo someone who has two displays perhaps to compare the figures from HWInfo. I just got rid of my spare GPU on MM on here so I can't reinstall that and check if there was a similar increase and thus indicate that this was normal behaviour rather than something Im overlooking. The second display really isn't used a great deal and I can easily just turn it off and save energy but it's bugging me as to the underlying cause!

Double07 · 21 Oct 2020 at 20:28

UnworthyBean said:
Have a double check what the clock speeds are in both single and dual monitor. I know with one of my older cards I checked if I only had a single display it would downclock lower than when I had dual displays which would explain the power draw.

Yeah it's definitely clock speed related with the 2nd monitor on. It jumps from around 150Mhz to 1900Mhz and the memory jumps massively too, guess Ill need to have a play about with that and see if I can see what's causing it! All at 1-2% GPU load.

Double07 · 22 Oct 2020 at 12:09

Mr Evil said:
I've heard of this happening when two monitors use different connectors. If you can, try connecting them both with DP.

That did cross my mind so I've ordered another DP cable to see if that makes any difference.

Double07 · 22 Oct 2020 at 13:15

Quartz said:
This is a known issue with Nvidia GPUs and multiple high resolution monitors and has been there for over a decade. There's nothing to be done. I have three monitors and the GPU is running at 1350 MHz and drawing 69W despite a 0% load.

Yeah I see a lot of threads about it online, however it looks like it can be fixed using Nvidia Inspector and forcing the GPU into power saving mode when multiple high refresh rate displays are connected and then only use the full power of the GPU when doing specific tasks, i.e. gaming or whatever by adding exceptions. I downloaded the program but I don't seem to have the option for setting it up on the version I have even though it's the same one as the youtube tutorials, etc!

Ive managed to get it down to 30W at idle by setting the second monitor to 60Hz rather than 75Hz, with the primary one still being 144Hz. So at least that's significantly better than before.

Double07 · 23 Oct 2020 at 11:41

t31os said:
Disable the secondary when you don't need it? (shortcut with Windows key + P). If that proves a problem with shortcut icons moving all over the place, grab a copy (freeware) of DesktopOK (google it), i don't turn my secondary off ever, but sometimes installs or driver updates like to ffffff shhh up and mess with the layout (the program is a simple save and reload icon position app, you can also save multiple restore points - it's non-intrusive, run when needed and forget it otherwise).

I just decided to plug the second monitor into a second PC which has my plex server on it and is on all the time anyway and is a low powered system but is fine for PLEX/Youtube, etc. I only really used it for watching TV/youtube on whilst using my main monitor for work, etc anyway so its not the perfect fix but it works fine and saves a fair chunk of power so it's worth it in the long run I guess.