PHPStorm used to “lag” for me before quite often too… but I managed to fix it in the following ways (It did take a bit of tweaking/experimenting though to get it to work! But now it is blazing fast once again!)
Here is what I did to optimize it:
1) If you are on Linux – Make sure you are using Oracle Java on your system, not Open JDK
From: https://intellij-support.jetbrains.com/entries/23455956-Selecting-the-JDK-version-the-IDE-will-run-under it says:
On windows: “JDK is bundled with all the product installers and it’s recommended that you will use the provided JDK version unless there are any specific issues.
32-bit JDK is located in IDE_HOME\jre directory and is used by the 32-bit product executable.
To run the IDE in 64-bit mode you will need to download and install 64-bit JDK (not JRE) distribution and install it yourself. IDE will find and use it from the registry when you run the 64-bit .exe file (available only for IntelliJ IDEA right now, other products can use the .bat file to run in 64-bit mode).”
2) Disable any plugins you do not ABSOLUTELY NEED! Especially any 3rd party plugins you may have installed**
GBC from PhpStorm 7 very slow and sluggish on netbook, optimize IDE for responsiveness? also had some insties:
3) Disable language injections: File -> Settings -> Language injections. un-check as many boxes as you’re comfortable with. HTML was the real killer for me.
4) Disable inspections: File -> Settings -> Inspections. uncheck as many as you don’t need.
I hope this helps!