One of the issues I have seen popping up over and over again the last year, is that the IDE starts to feel sluggish if I open up two different projects (in different windows). This especially seems to happen if you use the built in grep functionality to locate files/methods on larger projects.
When attending the PHP UK Conference last week, I had the chance to talk with one of the developers from Jetbrains that worked on PHPStorm. So I took the opportunity and asked how you could increase the memory limit.
While he recommended that I did not update the memory limit, the entire IDE feels a lot smoother now when I have multiple projects open after doing it. So if PHPStorm feel sluggish, I recommend that you at least try to increase the memory limit to see if it helps.
The steps to update the available memory/heap limit for PHPStorm is:
Note: For PHPStorm 8 on Windows 7
1. Locate your PHPStorm installation folder.
2. If you use the 64bit version, as an administrator edit the file bin/PhpStorm64.exe.vmoptions (If you use 32bit version, edit the bin/PhpStorm32.exe.vmoptions)
3. Change the line starting with -Xmx to -Xmx1024m
Note. You can change the -Xmx value to higher than one gigabyte, but I was recommended to increase it in steps due to making the value too large might also downgrade the performance.