I was on a conference call tonight with two other people where we are all working on an Unreal Project. We were discussing optimization and how some of the things we were doing were reducing lightbuilds rather well and 2 of us mentioned how our time was down to 21 minutes for this larger project. The other guy said wow, his time for the exact same project (we all pull the same project from GIT) was only 7 minutes. This made no sense. Me and the other guy who were at 21 minutes are using newer Ryzen 3950x machines with 32 gigs and 64 gigs of high speed ram. One is running a 3090 RTX and I am running a 2080TI RTX. Both of us have very fast hard drives.
The guy getting the 7 minutes is using an older machine with an Intel I7 and 64 gigs of ram with a 2060 RTX. We all ran the task manager when we were doing the light build and noticed the following in the UE Swarm. The Intel and the Ryzen had almost the same times and 100 % utilization of the CPU during the Caching Irradiance Photons. During the Skylight Radiosity phase, the Intel smoked the Ryzen since it maintained 100% cpu utilization and and Ryzens only managed maybe 9-14%. This is crazy. Then, in the final phase of Processing Mappings, The Intel slowed down and the Ryzen went much quicker with 100% utilization of the CPU. Still, it was not enough to make up the crazy difference during the Skylight Radiosity. My buddy with the Ryzen (like mine) was so ****** that he loaded the project on his other machine with an older Intel and the same thing happened seeing 100% utilization of the cpu from the Intel.
Can someone please explain to me how this is and is there anything that can be done to improve the Ryzen times? Thank you!