Swarm appears to be using only 4 threads on 12-core hyperthreaded processor

I have a new Core i7-12700K with 4 efficient cores and 8 hyperthreaded performance cores. Swarm Agent is using only 26% of my processor with 4 threads. Is there a setting that will try to make Swarm use all available cores? Is this a problem with Intel’s Thread Director? Will repeated use of Swarm train the Thread Director to make all the cores available?

Also, building AI paths seems to be taking a long time and the editor’s CPU usage never goes above 7.5%. Did UE3 just not make these tasks multithreaded?

When rendering on udk 2013-07 my i9-7960x (little of old now probably , but 16 core 32 threads) uses all of its cores.
But, if the scene is simple, not much going on like for example a empty scene like the day/night samples it goes like only 8-15% core usage. With my game level that is more complex it does uses all of the cores so its a matter of scene complexity? I actually remeber reading something like that before that confirmed that the triggering of cpu cores depends on the level complexity.

I think the change to hybrid processors in the latest generation has messed up Lightmass/Swarm’s access to the scheduler. I’m pretty sure previous processor generations, where all of the cores were the same, just made all of the cores available to Lightmass. I think that now Lightmass only sees–or Windows only offers–the efficiency cores. Task Manager’s affinity setting for my game shows that all of the 20 (virtual) processors are available to run it, but for whatever reason, Lightmass/Swarm only uses 4 of them. And that’s with a 509x509 landscape with thousands of rocks and trees that takes about 20-30 minutes to build. I’m sure it would go a lot faster with access to all cores.

Maybe I need to figure out which processor cores are the E cores, and change the affinity settings so that those cores never run my game, so that it’s forced to run on only P cores.

Was kind of away of the tech stuff and didn’t realized intel did something to the hyper threading as we know it.Just to make sure, there is no hyper threading option turned off in the motherboard bios or replaced with newer tech that you can change back there in the settings.

Just googled to see where this started and saw some news from 2017 when the sky lake and kaby lake cpus were coming out having hyper threading broken.Yours is way newer and problems should be ironed out, but maybe a microcode update or a third party app that will force it to work better? Is this on windows 10?

Another thing that comes to mind is that when you finished rendering a scene>open the swarm window>settings>ShowDeveloperMenu> and change that to True.
Now in the Developers Settings tab that will show up>LocalJobsDefaultProcessorCount>try to type in the number of processors.
In mine actually shows automatically the number 32 which are my threads.How many does your udk detects by default?

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Thank you! I would have never thought of looking for that setting. I just set that to 20 and tried building the same scene. I just saw my processor hit 100% usage and it blew through the build in 4 minutes. Yesterday it took over 20 minutes. Maybe my installation had kept some settings from when I copied my dev build over to my new machine. (From my old trustworthy i5 750, with DDR3 RAM and big 5.25" HDDs, which has now been retired to serve as the kids’ web browsing machine.)

There was nothing strange the BIOS. This is on Windows 11. The problem ended up being LocalJobsDefaultProcessorCount. Thanks so much for showing me that setting. If we were in the same office, I’d be buying you lunch today.

Glad it worked mate!

Enjoy the cpu!