Getting a capture card helps alot on capturing in game footage, it also relieves alot of stress on your CPU. The quality of those videos depends on the resolution that they have their game at. Editing in Vegas won't do you any good if you recorded footage that's 720p (because your monitor can only go up to that resolution) when you want 1080p as the big youtubers usually put videos out as. Your graphics card should be able to play games at ultra/max settings but you gotta capture that using OBS (Open Broadcaster Source) if you don't wanna get a capture card. It's all depending on your resolution though of the game when full screened. I wish you luck! I don't wanna leave my skype but I hope my information does good for you!