It seems that the performance of IntelliJ on MacOS is much better with JDK 1.6, than with 1.8.
I've been using IntelliJ on MacOS with JDK 1.8 now without major issues (except for some poor performance...) but with the recent 14.0 EAP builds, I first downloaded the version without JDK - which installed and ran on JDK 1.6 on my Mac.
Then I thought, hey, why not upgrade to JDK 1.8, since the JDBC drivers which I have configured are for JDK 1.7 or higher so they don't work... So I downloaded the version of 14 EAP with bundled JDK.
Then I realized that my IntelliJ had been running really snappy on the JDK 1.6 but was really quite sluggish on JDK 1.8, possibly even more sluggish than 13.1 was on JDK 1.8!
Switching back to the other installation, which runs on JDK 1.6, and performance is again very good.
I'm not sure but I do think that JDK 1.8 uses more RAM - however that shouldn't cause a slowdown as the machine has plenty of RAM to keep up with an increased use by IntelliJ.
Does this mirror the experience of others?
NB: In case it's relevant, I use IntelliJ almost exclusively for development of a Grails application, so my performance observations are limited to editing of Groovy files.