It may be a beginner but I am in trouble.
The Unity 2018 editor on my PC is very slow, only about 10% than Unity 2017.
Looking at the profiler, the value of “Shadow / Depth” in “GPU Usage” is always high, even if no game objects are displayed.
I think the computer specifications are not so bad, but why?
spec
OS:windows10Pro
processor:Intel(R) Core™ i7-4790 CPU 3.60GHz
RAM:32.0G
64bit
GeForce GTX 980
@ sx-arai, Your PC specification is good. it might not be the problem. There might be another problem. Does it happen in the Blank Project (Create a new project and check it)? Also if it does not help, try installing the latest Unity Version.
Mine is Unity 2019.1.7f1 and it works as expected even in lower PC configuration than yours. While downloading and installing Unity, Please do not use Unity Hub, instead use Unity Offline Download file (click here) and install it manually. Unity Hub is problematic. Hope you know how to install and configure.