[SOLVED] When I duplicate displays, my main screen video game is slowed down. 2080 GTX

[jon166]

If I either use an HDMI to my TV or to a capture card, the frames slow down in my main game.

It's highly noticable and I feel like this shouldn't happen with a 2080 GTX, and I felt like it didn't always happen.

Really don't know what's going on.

Is it because my main screen is 144hz and i'm sending out 60 hz?

If I change to show only on 1, everything is so smooth.

 

[jojesa]

The second monitor affects gaming performance . With a 2nd disply the GPU has to do more work at at once.
The fps drop will be related to the tasks you are doing on your second monitor,

 

[jon166]

is it really that much??
i could of sworn there was not enough gpu intensive just to duplicate the signal
but idk

The capture card is a Game Capture HD60

 

[jon166]

i think it's the passthrough is bottle necking it
i've tried all these things to get the monitor to stay at 144hz while sending 60hz but
i think windows update or gpu updates make it so that doesn't work

 

[MadsModsat]

I did a quick test, just to try to get an idea of what you are experiencing - and I have a similar GPU.

I use two 1440p monitors @ 144Hz. Both are DisplayPort. G-Sync disabled for this test. RTX 2080 Super / i9 9900K (stock).

When I set "Extend These Displays" in Win 10 and run Far Cry New Dawn built-in benchmark, showing in full-screen on monitor one, but the desktop is extended so the second screen is visible for other windows and tasks - but nothing running on hte second screen, i get

Min FPS : 89
Avg FPS : 114
Maximum FPS : 148
Frames Rendered : 7504
Screenshot : Extend These Displays - 1 Fullscreen and 1 idle screen

When I keep "Extend These Displays" in Win 10 and run Far Cry New Dawn built-in benchmark, showing just on monitor one (still full-screen), but also running a full screen YouTube video on the second monitor, i get

Min FPS : 82
Avg FPS : 110
Maximum FPS : 140
Frames Rendered : 7200
Screenshot : Extend These Displays (two fullscreen apps : game & Youtube)

If choose "Duplicate Displays" (the game showing on both monitors), and run the same benchmark I get

Min FPS : 89
Avg FPS : 114
Maximum FPS : 148
Frames Rendered : 7502
Screenshot : Duplicate Display (almost identical performance to the first test)

So the performance is not really severely impacted, by any of theese setups.


However -> I wanted to test with one screen at 144Hz and one at 60Hz, because I was under the impression that's how OP had the settings set.

But in my case, both monitors were forced to the same refresh rate (which seems to be determined by the lowest refresh rate - which makes sense), when I activated "Duplicate Displays". I can use different refresh rates when extending displays.

So the only potential issue I can see with OPs setup is, that the main game is only displaying at a 60Hz refresh rate determined by the capture card, and if you are used to a higher refresh rate, the game would appear choppy if you are playing the game at just 60Hz - only if you are seeing a framerate above 60 FPS of course.

So I suspect that it is the reduced refresh rate that gives the impression of poor perfomance when duplicating displays, because as far a I can see, the potential peformance is pretty good despite running two different full screen application simultaniously (although just one actual game and one stream).

But I might have missed an obvious difference - I just ran three quick teests, and they are not very scientific, so to speak (and just one single game).

But it still makes me suspect that the possible refresh rate descrease to 60Hz in Duplicate Displays-mode, caused by the max refresh rate of the capture card, is what's causing the issue.

 

[MadsModsat]

Maybe this could be of some use?
How to use a 144Hz / 120Hz monitor with a 60Hz Elgato Capture card (Nvidia GPU)