Linux: Steam games ran slower with USB-C power than on battery due to undersized power delivery

This is unbelievable...

Discovered this while looking at the PowerMizer section in nvidia-settings.

When the Power Source item is Battery, Performance Levels oscillate between 1 and 2, and Graphics Clock operates normally.

However, (probably) if power is supplied via USB Type-C and the power amount is slightly insufficient, the Power Source becomes Undersized.

In this state, Performance Levels might still be 1 or 2, but when a heavy process like a game starts, Performance Levels drop to 0, and Graphics Clock also decreases sharply.

It seems that things other than games are also slowing down due to this.

I can't believe supplying power actually makes it slower...

I'll investigate AC power supply and other methods later.