Newest build seems to have trouble with 4k

[Nolonar]

I just downloaded the newest build and noticed that all of my games were capped at 30 FPS, whether they're Wii games (tested on Mario Kart Wii) or NGC ones (tested on Mario Kart DD).
It's not just the framerate that's halved, but the games' speed as well; as such, the audio was playing at half the speed too.
I know my computer should handle 4k just fine, since I had played Mario Kart Wii at 60 FPS in 4k before, so I decided to experiment with my settings for a bit.

Changing Framelimit from Auto to Off didn't change anything, so I left it on Auto.

Changing my Fullscreen Resolution from 4k to FullHD fixed my issue.
Keeping my Fullscreen Resolution at 4k and changing Internal Resolution from Auto (Multiple of 640x528) to 4x Native fixed my issue.
Keeping my Fullscreen Resolution at 4k and my Internal Resolution at Auto (Multiple of 640x528) and enabling Borderless Fullscreen fixed my issue (I didn't expect that one)

So it looks like Dolphin has trouble with 4k (3840x2160) while in Exclusive Fullscreen mode.


My rig in case it's relevant:
i7 3770K @ 4.2 GHz
32 GB RAM
GTX 680

[DJBarry004]

Make sure VSync is off. When a small slowdown happens (less than 5 FPS?), it´s known for VSync to do things like that.

[JMC47]

4K resolution stresses out your CPU more. The communication between CPU and GPU takes up more and more bandwidth for stuff like EFB Access and whatnot. You're basically maxing out your processor (and maybe GPU too,) through raising the resolution so high.