What hardware are you running on?
Perhaps try a clean install? I have the same MBP (with Radeon 455) and Finder works just as it did in HS).2016 15" Macbook Pro with the 2.6 and the 460pro.
It takes literal seconds to complete a task in Finder. You double click, and you have a good 1-5 seconds before anything occurs. After an hour with Apple support today, it appears the only fix is to roll back.
I have a similar machine as yours and Mojave is super fast. I did a clean install with FileVault encryption, by the way encryption took only 25 minutes to do it's job with a 250GB drive.
I just purchased a 2017 21.5" iMac. I have not upgraded yet - it has been acting slow and funky since I got it a few days ago. It is brand new. Do you think the update will help it? I am probably going to return it to BB in a few days. I need to be able to upgrade the ram.Speed and responsiveness feels about the same as HS to me on a 2017 iMac, which is quite good.
Wait.... Apple officially suggested you don't use their latest operating system on a 2-year old MacBook Pro? I mean, even if Mojave was slower, Apple would never suggest you don't use their latest OS. Not sure who you talked to, but I think they just didn't want to deal with you.No – it's rollback time. That's the only solution Apple could identify.
After an hour of support chat that's all they had to offer. They suggested I use a backup to roll back the operating system.Wait.... Apple officially suggested you don't use their latest operating system on a 2-year old MacBook Pro? I mean, even if Mojave was slower, Apple would never suggest you don't use their latest OS. Not sure who you talked to, but I think they just didn't want to deal with you.
Anyway, as many, many people here can attest to - Mojave does not work slower on supported Macs, and waiting a few seconds in Finder is not normal and may be indicative of some problems with your Mac. It's not Mojave.
I noticed in GLView there are more portions of OpenGL supported. Not as many as windows but more than under High Sierra. This implies there is more graphical optimization for OpenGL despite the fact it is supposedly "deprecated".Cinebench tells me openGL is 33% faster, I used to get 77 fps, now 104.