Reproduction steps:
1. Open the attached “Test Project” project
2. Go to Project Settings > Player window
3. Make sure the “Run In Background*” option under “Resolution and Presentation” is unchecked
4. Build and Run the Project
5. Observe the “System Monitor” application’s “Resources” tab while the Player is in the foreground
6. Observe the “System Monitor” application’s “Resources” tab while the Player is in the background

Expected result: The CPU usage is the same as when the Player is in the foreground
Actual result: The CPU usage is a lot higher than when the Player is in the foreground

Reproducible with: 2021.3.26f1, 2022.3.1f1, 2023.1.0b20, 2023.2.0a18

Reproducible on: Ubuntu 22.04
Not reproducible on: Windows 10