EDIT: The statement below is not valid for up-to-date Clion releases. Therefore this topic is solved and you should maybe open a new thread / report with specific problems.
Sorry to say - I just canceled my subscription after having terrible performance in the last weeks with bigger projects / and libraries in development.
It should be nothing new to you as the support channels are full of the same description:
1. Building symbols slow - about 10-30 mins. Only for as long as the CMakeFile is not changed as there is caching. Great but still my employer would be unwilling for me to spend up for an hour waiting for an application to open text files. I can not foresee that any of the refactoring functionality can make up for the lost time. Well if it did I'd live with it, but Eclipse offers similar functionality (at least in base tasks) and does not suffer from these interruptions.
2. Endless CPU bursts at 100% for several minutes, basically for every new file I'm opening or symbol I'm touching. And this time it seem not to cache that much. It happens over and over. Also if this was a background thing, ok but it literally freezes clion ever other click up to a point where nothing draws for 5 minutes. This game repeats itself longer than any human being has patience. This is not a background task anymore, and it makes any development impossible.
Memory usage is not even its peak. Yes, I tried adjusting the heap via VMOPTIONS. Also I disabled Reflow and set the inspection level down. Even Power safe mode. Still it is not noticeably better. Ok let's be extreme: Power saving mode, Slider to None, all C++ inspections of. Freeze. Really?
If I disable all functionality I can pretty much just use vim right away and safe the money. I haven't figured a sane setting yet.
To be fair: In smaller, home projects with minimal dependencies Clion performs pretty well. And when it rolls it rocks. It is just not worth its money in my personal opinion, yet.
I look forward to be proved wrong in future versions: Here is a benchmark for you. Download Pixar's OpenSource project USD. Build the couple of requirements (lastest Fedora has most of it). Anyone can test this for her/himself.
At the point where I can develop in this library or similar without these interruptions you will have me back as a customer. Meanwhile happy optimizing.