I’ve noticed the following issue when using -DX12 on commandline when launching independent game instance, editor build, with UE4 editor closed the whole time (just the game running)
a. at 1920x1080 desktop resolution and windowed mode with the window set to 1920x1080, I get 120 fps on my TITAN X graphics card
b. when I press Alt + enter to go to windowed full screen to remove the title bar on the UE4 window, then my fps instantly drops to an unstable ~60 fps frame rate
c. vsync is turned off
d. again my desktop / OS resolution is 1920x1080
e. Same steps in DX11 does NOT cause the complete tromping of my frame rate from 120 fps to ~60 fps, my frame rate stays solid 120 fps in windowed fullscreen 1920x1080
Do you know of any reason why just by going from windowed to windowed full screen in -DX12 that the frame rate would get so smashed?
I consider this very important cause I’d rather use DX12 windowed fullscreen, but currently I have to have that title bar visible to get 120 fps (windowed not windowed fullscreen)
I was unable to reproduce this issue on our end. I have a few questions for you that will help narrow down what issue it is that you are experiencing.
Quick questions:
Can you reproduce this issue in a clean project?
If so, could you provide a detailed list of steps (including any small steps that may have been left out of your original report) so that we can reproduce this issue on our end?
Could you provide screen shots of any settings that may be involved with this issue?
I downloaded the Elemental Demo 4.13 and ran it with 120 fps cap and -DX12 and was getting solid 120, whether windowed or full screen, so I will need to do further research and possibly come back with some realizations on this matter. The good news is that hopefully my report is a fringe or isolated issue and others are not affected. I will try to get back on this topic within 2 weeks.
We have not heard back from you in a few days, so we are marking this post as Resolved for tracking purposes. Feel free to reopen the issue when you have completed your additional testing. Just provide any information you may have and we will follow up.
