I use UE4 on a rMBP (with a GeForce 750m), and it runs really well (60fps, editor). The only issue I am having with Unreal is that is uses huge amounts of CPU while editing. After profiling the editor, it appears that most of the CPU time is being wasted by Slate (the UI). Could somebody look at this for me?
As you can see by the highlighted lines, Slate is using 65% of my CPU (while rendering uses the other 10%). Fixing Slate would make the Editor much faster, and would also make the Launcher use less CPU (it uses 10% on my Mac).
This has already been marked as solved, but it would be great if it could actually be fixed.
EDIT:
I got around to testing it on my desktop (Phenom II x6 + GTX 550ti on Windows 8.1), and get the same result. Pretty much the same CPU usage while editing with realtime off (60-70%). I don’t have a profiler on that machine, but I would guess that it is also Slate.
We are really eager to make slate consume fewer CPU resources. However, there is some non-trivial work necessary to do that. I hope we get around to it soon, but I cannot give you any sort of timeline for it.
I am also not sure how quiet we can make the laptop experience. Ultimately, whenever you do anything non-trivial with you CPU/GPU, those devices heat up. Doing something like a lighting build can push every single core of your laptop to the limit, which will generate a lot of heat. Afterwards, it may take a while for the temperature to drop and your fans to spin down.
EDIT: If you have 4.3 version of Unreal, you should find the CPU consumption by Slate somewhat reduced.
You could try limiting the refresh rate of the editor’s window using t.MaxFPS console command and/or disabling realtime refresh in viewport’s settings. It won’t help for tasks that use a lot of CPU/GPU resources (shader or code compilation, lighting building), though.
That screenshot was taken with UE4.3.1 with the ‘Reduce CPU consumption in background’ option unticked, as I wanted to log performance while I was using it. I realize that lighting builds are taxing on the system, but the editor causes my system to spin up even while doing nothing (simply having it in the foreground on an empty scene, which is how I profiled the editor in the image).
(same text that I added to the OP):
I got around to testing it on my desktop (Phenom II x6 + GTX 550ti on Windows 8.1), and get the same result. Pretty much the same CPU usage while editing with realtime off (60-70%). I don’t have a profiler on that machine, but I would guess that it is also Slate.
Workaround, but not a solution:
On Linux/OSX you can use CPULIMIT to cap the CPU usage, which is good for simple editing.
on OSX run brew install cpulimit
then, find the Editor PID from activity monitor. Run:
