4090 (poor) performance

Yep all the latest drivers. It’s looking more and more like CPU bottleneck is the issue. Another 4090 owner (not a Notch user) upgraded to a 13900K and it fixed their problems. I’m gonna limp through with this performance until the 14th gen stuff gets released.

I’ll attempt to sort out some of the confusion here. The issue here is probably not down to choice of power supply, PerfCap/VRel or anything like that. When people talk about bottlenecks it suggests incorrect use of hardware or that somehow something is broken in the software (or the PC itself) that needs fixing. It’s not. This is simply about the scene’s GPU load vs its CPU load.

It is possible for Notch scenes to be CPU-limited, not GPU-limited - particularly if the GPU load in the scene is not that high in the first place, and there’s lots of work being done on the CPU. There’s all kinds of reasons why this can occur, but it depends on your scene / nodes.

In the case where the scene is CPU-limited, using a faster GPU won’t improve performance. Using a faster CPU may help, but the best solution is to reduce the CPU load in the scene by optimising it.

The single biggest, most likely cause of being CPU limited is running in Builder. Builder’s UI runs outside of scene rendering and puts lots of load on the CPU. If you export to Standalone EXE (or a Block) this load goes away entirely: the fastest GUI is one that doesn’t run at all.
If you are running a project in Builder, it will always be slower than it could be.

Next, determine whether the scene is CPU limited or GPU limited. You can easily test this by reducing the GPU load and seeing if the performance goes up. In most scenes you can do that simply by rendering to a much lower resolution - as most of the frame time is spent on rendering to screen - but in some scenes such as those heavy on simulations it could be that you need to cut e.g. particle count or field resolution down - so it depends on the scene itself. If you do this and the performance improves dramatically - e.g. doubling when you reduce the resolution in half- you’re most likely GPU limited and you should focus effort on optimising GPU load - or, of course, get a faster GPU! If it didn’t dramatically improve performance, you may be CPU limited and you should focus your efforts there.

Optimisation strategies for CPU or GPU limited scenes are beyond the scope of this post, but if you need specific help Notch Support is always available if you get in touch.


I think this needs to be a very nerdy tshirt.