If you have installed PHP Storm on your Ubuntu x64 system and you are not getting smoother font then locate phpstorm installation folder and open "phpstorm64.vmoptions" file; in my case path was
/opt/PhpStorm-145.258.2/phpstorm64.vmoptions
then add these three lines to end of the file , save , restart your IDE, enjoy
⚠️ Dont touch any existing lines in original file