Wow, that’s pretty weird… In the past, I’ve tried clearing out the DCC cache in my AppData\Local\UnrealEngine\4.18 folder and that never did anything anything, but switching it to -ddc=noshared caused my fps to almost triple in the editor viewport? (I made sure the cache location changed, and within the ue418 install folder, there’s a DCC folder now and within the project folder, there’s also a DCC folder)
Now I should note that I haven’t had my editor open for a few days and in that time, my Windows updated to the fall creator edition, so it’s hard to say if it was a windows issue or if that noshared option did the trick. Guess I’ll never know now lol…