How capable is this computer for 1080P Gaming?

Solution
It will not play, on max settings, many recent games AAA titles. Running triple monitors is very GPU intensive and even more so if you are going to run a game on all three. You will be looking at medium if not lower settings on many games. Older ones you can get away with and not have much issue, Crysis 3 and doom 2016, as an example, will bring that system to it's knees and make it cry.
It will not play, on max settings, many recent games AAA titles. Running triple monitors is very GPU intensive and even more so if you are going to run a game on all three. You will be looking at medium if not lower settings on many games. Older ones you can get away with and not have much issue, Crysis 3 and doom 2016, as an example, will bring that system to it's knees and make it cry.
 
Solution