Why does my GPU Load change when switching screen modes?

[Fulano5321]

I'm testing video issues with my 1GB 9800 GT in Age of Wonders 3, the game has a "fullscreen" setting and a "borderless" setting.

I noticed when I use "borderless" my GPU usage is about 85% and the temp hangs around 60 C, but the framerate feels a little lower.

Otherwise when I use "fullscreen" mode the GPU Load is maxed, the card gets 65 to 70C but the framerate feels better.

What's the difference? What's changing between the two modes? I suspect the borderless is the same as windowed, just without a border, but why would the GPU load go down when I use it?

It feels like something else is bottle-necking but GPU-Z doesn't show anything else maxed out.

The Memory Controller load hangs between 20 and 30% in both modes.

I've got 8 GB RAM and an i5 4590, so those are well above the recommended game specs.

 

[JamesSneed]

Yes Im assuming its windowed mode.


When an application runs in full screen mode, it runs in "exclusive mode". That means it has full and direct control over the screen output.

But when it runs in window mode, it needs to send its output to the window manager (windows explorer) which then manages where on the screen that output is drawn. This takes some additional performance. Also note this time dealing with the window manager will be CPU time not GPU time so it may very well explain less load on the GPU but lower frame rates. If you are trying to get the most performance then run in full screen mode at the native resolution of the monitor and yes you should see more load on the GPU in this case but that is exactly what you want to see.

I'm sure you are already aware the 7+ year old 9800 gt is by and large your bottleneck when playing games so if full screen mode at the native resolution doesn't do it for you I would start looking to upgrade the GPU.

 

[Fulano5321]

Yes Im assuming its windowed mode.


When an application runs in full screen mode, it runs in "exclusive mode". That means it has full and direct control over the screen output.

But when it runs in window mode, it needs to send its output to the window manager (windows explorer) which then manages where on the screen that output is drawn. This takes some additional performance. Also note this time dealing with the window manager will be CPU time not GPU time so it may very well explain less load on the GPU but lower frame rates. If you are trying to get the most performance then run in full screen mode at the native resolution of the monitor and yes you should see more load on the GPU in this case but that is exactly what you want to see.

I'm sure you are already aware the 7+ year old 9800 gt is by and large your bottleneck when playing games so if full screen mode at the native resolution doesn't do it for you I would start looking to upgrade the GPU.

Interesting. The framerates seem good both times, not too worried about performance as it does what I need it to. I play very CPU intensive games so this video card that I picked up for $15 at a Black Friday sale a few years ago has done well, though I suspect it's fan might be starting to go out...

I'll watch the CPU usage and see if there is a difference. I just learned how to watch the framerate in the game too so I can double check that. Thanks!

 

[JamesSneed]

Welcome.