Fullscreen slowdowns disappear when focus is lost

[RemagOrter]

Hi, i tried to solve the few problems i had with Dolphin on my own.

I use Dolphin in Exclisive Fullscreen mode.
While i experienced some slowdowns, due to too high internal resolution (x4 instead of x3) and Per-Pixel Lighting ON (instead of OFF), at some places ingame (for example in Super Mario Galaxy), i ALT+TAB to the Dolphin window to change settings, BUT...
At this time the Exclusive Fullscreen is running in background and the focus is on the Dophin window, AND the slowdown is mysteriously gone. The Game runs in Fullspeed in background, still playable (Background Input enabled).
If i ALT+TAB back to the game the slowdowns are back. So i decided for few games to force the Fullscreen to loose the focus, so i can play at higher resolutions (not really a good solution, but it works for me for now).
BTW this happens on all Backends OGL, D3D and Vulkan.

Sooo...
My questions for today are:
Do you have made similar experiences?
Is this just luck it works?
What causes this weired performance mystery?

So far, thank your for your time.

My System:

Windows 10 x64, i7 7700k, 32GB DDR4 RAM, Nvidia GTX 1080 Ti, USB Bluetooth Stick SENA UD100 (WinUSB Driver)
Dolphin x64 5.0-9595 Auto Update: Dev (multiply times a day)

[RemagOrter]

Since i used Display Driver Uninstaller to solve other problems, this doesn't work anymore for me.
For example in Super Mario Galaxy the slowdowns randomly start and stop every ~ 2 minutes and last for ~20 seconds. (Fullscreen focus lost)
Can this have something to do with the way shader compiling (or other things) is done by Dolphin, and the lost fullscreen focus is intefering with the data flow somehow? (Still a DAU here, not knowing what i'm talking about)
I'm just curious.

[DJBarry004]

If you´re not using any of the Ubershaders settings, then the stuttering is normal when playing the game for the first time/playing new zones/etc.

If you are, then Windows is messing with you.

[RemagOrter]

Thank you.

[DaRkL3AD3R]

Check your GPU clock speeds. I don't know why you would have any slowdowns with that rig at 4x or 3x IR. I run 6x IR at all times and have massive amounts of power to spare, and we have identical rigs. Basically what happens is, if your GPU is set to "optimal power" in the nvidia control panel, then Dolphin will be so light on the card at 3x IR that it will stay downclocked when it shouldn't. Try setting it to Prefer Maximum Performance and then reload Dolphin and try again. It should run better now in exclusive fullscreen.

By the way good job on actually knowing what that is. It's depressing to me how few people seem to care anymore that exclusive fullscreen exists and why it's better for ultimate performance and frametime pacing, so respect to you for knowing and using it.

[JMC47]

The other thing it can be is vsync. Vsync can cost a lot of performance.

[RemagOrter]

Thank you 2.
I checked the Nvidia Control Panel Settings and you were right. After reinstalling the Display drivers i forgot to set Dolphin to prefer max power again That helped a lot.
I can now play Super Mario Galaxy with 5x IR and all enhancements you can imagine (except Anti-Aliasing, i have to use 8x MSAA instead of 8x SSAA) at 60 FPS without any slowdowns ever. If i then go to 6x IR the FPS drop to 45 -55 FPS. Deactivating Per-Pixel Lighting gives me 60 FPS at 6x IR. But that's totally fine i think.

To the Exclusive Fullscreen mode: I noticed gamechanging latency using Borderless Fullscreen in games like Rhythm Heaven Fever. But i noticed this kind of latency everywhere, not only in Dolphin. Regular PC Games have this too if they offer Exclusive/Borderless Fullscreen. In most games it doesn't matter. And RetroArch have the same thing, so i asssumed this is something Windows does and stand away from Borderless Fullscreen just for safety.

@JMC47: Deactivating VSync helped also. I was able to go up to 6x IR in SMG and Metroid Prime 3, but now i got eye cancer (sorry, not funny). Jokeing aside, i'd rather play at 45 FPS than deactivating VSync ever again lol. It's like playing the top and bottom half of the screen through a timetunnel, or like i got a broken tv. I don't understand how people can play with VSync deactivated.
Could it be my TV that makes this effect so bad? Is this less noticable on real PC Monitors? I have an Philips 47PFK7109/12, changing TV settings from TV to Game to Computer didn't help.

Again thanks a lot for your help.

[DaRkL3AD3R]

Personally I would much rather use higher IR and little to no AA since AA only cleans up jaggies, it doesn't actually increase render quality like IR does. Better to use like 6-8x IR and FXAA if you must clean up jaggies at all. Better use of resources IMHO. As for v-sync, it shouldn't actually cost any performance but if you are dropping frames with it enabled, try enabling Triple Buffering in NVCP for Dolphin. If you use DX11 backend instead of OpenGL or Vulkan than use Fast Sync for Dolphin v-sync setting instead and turn off v-sync in Dolphin. That should clear up frame drops with v-sync.

[RemagOrter]

Thanks, i made the same experience. Higher IR over AA.
To the VSync it's not dropping frames, it's like you take the frame, cut it in 2 parts and put it wrong together again. But i was able to find the reason for this. It's definately my TV. I tried Dolphin on my old 15" Monitor and i barely notice any chpped frames. I'll get an good PC Gaming Monitor later today from an friend to test it again but i need to buy a new TV/Monitor.

Any tips for a new TV i could buy for using mainly as PC Gaming Monitor?
Thanks again