I have searched some articles online says there are ways to optimize the speed with jdk 1.7, but by changing jvm memory size seems not working with jdk 1.8 version.
any solutions to this issue ? thanks.
Some things which you should consider for optimizing performance: * Memory: this is the most important point IMHO, but you have written that you have changed the setting already. Are you absolutely sure your config has been picked up? E.g. there is separate config file for 64 / 32 bit. * Disable plugins: Make sure everything you do not not need is disabled. This way IntelliJ also starts up faster.
See also: https://www.jetbrains.com/idea/help/tuning-intellij-idea.html
If this still does not help, please provide more information what exactly is very slow.