performance issue if screen turned off

- [x] I have read the [FAQ](https://github.com/Genymobile/scrcpy/blob/master/FAQ.md).
- [ ] I have searched in existing [issues](https://github.com/Genymobile/scrcpy/issues).

**Environment**
- OS: [Windows]
- scrcpy version: [2.3.1]
- installation method: [Windows release]
- device model:oppo a7, Samsung galaxy f34
- pc: Acer gateway ne46RS1 laptop (2gb,dual core, windows 10)
- Android version: [8,14]

**Describe the bug**
The frame rate or the performance is reduced on output screen if I use "scrcpy --turn-screen-off" command. Without this command, the game runs smoothly both on phone and pc.

(I'm currently having one phone, so, I can't show it as a video)

On errors, please provide the output of the console (and `adb logcat` if relevant).

```
Please paste terminal output in a code block.
```

Please do not post screenshots of your terminal, just post the content as text instead.

Start by reproducing the reported performance difference on Windows with scrcpy 2.3.1, comparing normal use with `scrcpy --turn-screen-off` on the listed Android devices. Done means the cause is identified and the reduced frame rate or performance is resolved or clearly documented with reproducible results.

Written by the indexing model from the issue text.