Laptops and gaming are ok, as long as you provide enough cooling. Make sure the vents are well cleaned from dust. Grab a can of compressed air and shoot it in the vents. Make sure you pass it thoroughly. You can use an air compressor for that matter, as long as it doesn't shoot out water (Big compressors).
Also, make sure you're playing on a hard surface...just in case you're a bed gamer
Last but not least, get a cooler for the laptop on the bottom.
Oh and...running it on battery will make it slower, because the default settings are set to save as much juice as possible.