How to check my graphics card?

My brother dropped my laptop today; everything but the graphics seems fine. It is a Lenovo Y510P, with dual graphics cards (using the ultrabay). I think the one in the ultrabay is a little shaken up? When unplugged it has always run a bit slower, but fine otherwise. Now the screen flickers, as if the frame rate were off. But when I plug it back in to the power outlet the flickering stops and performance is increased. I don't trust the increase performance when plugged in, because the main GPU could be taking over then. Is there a way to do isolated testing on the ultrabay GPU?

The built in GPU is the slower one and that is the one which is working when you are NOT plugged in. It is supposed to switch to the better GPU when a) you need it for performance reasons and b) you are plugged in. There should also be a key combination/command to force it to switch. The idea is that when plugged in you have the juice to power the better card, but on battery it sucks down too much power, killing the battery life.

I suggest you check to make sure the card in the ultra-bay is properly/firmly seated and undamaged.

Is the ultrabay fan functional? Could be overheating.