Fullscreen doesn't fully stretch

[PsychonicJoe]

Hi,
I can't seem to get Dolphin to stretch the screen to the whole monitor, i get big black bars on the sides, my monitor is 1366x768 and am playing at 800x600 (don't blame i need maximum frame rate) i tried messing with aspect ratio settings but nothing worked, auto adjust doesn't work either, the screen does fully stretch when using windowed mode but i prefer to play fullscreen.
Am running Windows 8.1 and using Dolphin 3.5-175 (yes, because all newer versions have choppy sound for SSBB)
Thanks.

[cyrax33]

We would not be able to provide assistance on an outdated version, either update to the latest dev. build and see if it remedies it or use the search to look for possible solutions.

[KHg8m3r]

You shouldn't be having issues with the latest dev builds, your CPU seems fine.
Under the graphics tab, check to see what you have the Aspect ratio set to