Didn't mess with the resizable bar yesterday just sat back and played a game for a while. Tiny Tina's Wonderland with the 1080ti I had to dial back more than a few settings @4k to keep 40+ fps on the 1080ti, some lighting effect especially would just tank the frame rate until I basically turned off most shadows. With the 7900xtx cranked absolutely everything as high as it would go and didn't enable any of the DLSS equivalents or anything like that and it typically held 90fps or higher at native 4k (Monitor is only 60hz refresh rate), except for the cutscenes they seem to be fixed at 30fps.
I did notice a small vibration in the GPU cooler that is annoying, the waterblock is still out of stock. Did order a 3 pack of 180' power adapters so I can get the side panel back on for the time being. When I do get my hands on the waterblock I'll take the final measurements etc to see if I have to vertical mount or not.