I love using @intellijidea @jetbrains but ever since I installed High Sierra it now uses 300% CPU and my machine crawls. Quiting and restarting the IDE helps as does disconnect 2nd monitor then reconnect. I even updated graphics driver. But 5 min later slow again!
there are e.g. https://youtrack.jetbrains.com/issue/JRE-525 https://youtrack.jetbrains.com/issue/JRE-526 but not necessarily High Sierra related