Laptop has greater than usual fps problems when unplugged

[VonShnitzel]

For the last few weeks, my gaming laptop has been having serious framerate issues on some of the more taxing programs (video games, animation, etc.) when it is unplugged. It is much worse than you would normally expect from an unplugged laptop. Mine is getting less than 5 fps for almost everything.
There doesn't seem to be any pattern to it either. Some of my older games will have this issue, while some of the newer, prettier ones will work fine, and vice-versa. This is really strange because I used to be able to run Far Cry 4 on max settings at 1080p with minimal fps drops.
Does anybody know what the source of the problem might be, or if there is any fix for this? Thanks in advance

On the off-chance that this might be important information:
Lenovo Y50-70 Touch
-Nvidia GTX 860M
-Intel i7-4700HQ 2.4 GHz
-8GB RAM

 

[xbizzaroz]

When you unplug the laptop it automatically goes into a low power state so both the CPU and GPU operate slower to conserve power. It's actually normal for a laptop to do this.

 

[xbizzaroz]

You can turn that option off in the settings too by the way.

 

[DarkSable]

Also, check for dust. I'm betting things are plugged up and the chips are further throttling from heat.

 

[VonShnitzel]

You can turn that option off in the settings too by the way.

Where would I find that option? I doubt that this is the case (it ran perfectly fine for a long time, then just started acting up one day), but it would be nice to check it just in case.

 

[xbizzaroz]

Check in your Nvidia control panel. The setting should be in there.