If you are working on a full-stack project, you may see a CPU warning appear in the App Stats within the Project Editor as the project is starting up.
In most cases, the warning will disappear once the project finishes loading. If the warning disappears, and your project is working fine otherwise, you do not need to adjust your project to reduce CPU.
This warning is being triggered by a system adjustment we made to improve the overall install time for all apps on Glitch. Improving load time is a work-in-progress and part of that will involve preventing this warning from appearing during startup in the future. In the meantime, if you have any questions about this, please contact Support.