Noticable update event slow down, when laptop is disconnected from power

[BeldrothTheGold]

Hello,

I noticed today when I disconnected my development laptop from power, game updates in my, very simple, Tetris clone slow down noticeably.

To confirm the issue is not with my game code, I tested this on the piston getting started tutorial code and see the same slowdown occurs there. Attached a GIF of what I am seeing. You can clearly see the slowdown when the laptop is disconnected from power, and then speeds up when reconnected shortly after.

This seems like it shouldn't be normal behavior, right?

[BeldrothTheGold]

A similar example made using using Bevy engine, becomes noticeably less smooth when the laptop is disconnected from power, but it does not slow down.

V/R
Scott

[bvssvni]

Could it be a bug in the OpenGL driver?

[BeldrothTheGold]

To be clear the black artifacts seen in the gif are not present on my PC. What I'm seeing looks like a consistent decrease in the number of update events the game code is receiving from Piston when I unplug.