So this issue has been plaguing me since 2022 when I first started using UE5, consistently the same issue across every version of UE5 released in that time. For reasons I cannot determine despite spending YEARS looking for answers, my main PC runs UE5 at least 50% worse than it theoretically should. I have tested this across personal scenes, sample scenes, project files shared by other creators, template scenes, etc. It’s all the same
On my main PC (5950x, 64GB RAM at 3600, RTX 3090) I can measure how my editor and PIE/Standalone tests run, fps and frametime. Then copy that project to different PC with worse specs (5600x, 32GB RAM at 3200, RTX 3070Ti) and I will instantly double or more my performance. Again, I am COPYING THE PROJECT, so every single assets, file, setting, etc is IDENTICAL between the PCs, nothing is changing except the PC itself, which is essentially getting worse but performing better.
Some examples of frame rate:
Virtual Studio sample scene from Epic
Main PC: 65-75
Second PC: 110-120
My own person scene
Main PC: 55-65
Second PC: 95-110
Project file given away on Artstation
Main PC: 60-75
Second PC: 100-110
Empty test map (The one with the large flat terrain with hills on the outside edges)
Main PC: 75-85
Second PC: 130-150
Totally empty map (Where the screen is black because nothing at all is in the scene)
Main PC: 75-80
Second PC: 300
I think this one is very telling. There is no reason whatsoever I should be getting about 10 FPS more in a literally EMPTY map compared to the heavily populated sample maps used above. And yes I am disabling all editor FPS caps in these tests
Now here’s the important footnote that makes this confusing, It’s not down to some sort of hardware configuration problem. My PC runs everything exactly as it should outside of UE5. My gaming performance matches equally specced PC benchmarks available online. My Rendering performance in Arnold, Blender and Octane also match benchmarks of similarly specced PCs. EVERYTHING except UE5 runs precisely as it should on this PC. But UE5 just loses 50-60% of what should be its normal performance. In fact, I found someone who has a near 100% identical PC to mine (Only difference is superfluous) and he gets exactly the performance I should expect, around 100% better than mine currently is.
An addendum to this: One thing I find particularly strange is the lack of performance change as heavy settings are toggled on and off. It’s like all the extra performance I SHOULD be getting when I turn something off just vanishes into the ether. Like Lumen is relatively heavy for performance. So I go into my settings and I disable it, but there is almost no performance change (I gain like <5% at most) even though it IS clearly disabling (You can see a stark visual difference). When I test the same project on the other weaker PC, disabling Lumen shoots performance up significantly.