about idea cpu

Make sure that:

• IDE config directories, installation folder and project files are excluded from the antivirus/firewall scan
• the IDE is installed on a fast local drive and project files are not located on network drives
• unnecessary folders are excluded from indexing (mark them as 'Excluded' in the File | Project Structure | Modules | Sources dialog if you are working on a large project).

See if any of the following positively affects the performance:

• Increasing the heap size in Help | Change Memory Settings. If it is too low, Garbage Collection process runs too often, using up the CPU and slowing down the IDE. You can increase it up to 85% of overall available memory.
• Temporarily disabling all downloaded plugins (File | Settings/Preferences | Plugins | Installed | ⚙ | Disable all downloaded plugins) and restarting the IDE
• Switching runtime JDK to the default JetBrains Runtime in case something else is selected.

If the problem persists:

• Capture a CPU usage snapshot. To keep the readings clean and on point, start the profiling only when performance actually drops, and stop it right after you are done testing.
• Take a screenshot of the Help | Diagnostic tools | Activity Monitor window while experiencing high CPU usage
• Zip the whole IDEA log folder (Help | Collect Logs and Diagnostic Data) after reproducing the issue, then send everything over for analysis. If the attachments are too big, you can upload them privately to https://uploads.jetbrains.com/ and provide the upload id.

my mean is when idea work long 100% cpu,

then idea can notice user  pop-up notification,

user can click the pop,then idea can auto increase memory,

it's good to improve user's experience

i find idea already has this pop, 

why i click it, but it not change memory setting

Could you attach a screenshot of the popup that you are referring to?