viewing vga to usb input on a mac book pro

I want to use my mac book as a monitor and key board and mouse for my windows pc. basically i want to use my lap top as a remote control for a headless windows 7 pc without lag. I want to play some steam game that is very graphic card Intensive. I do not want to use a slow wifi connection to do this. one option would be to just display the GUI of the pc on my laptop via a vga to usb adapter. Another option would be to use a ethernet connection from my pc to my mac laptop using vnc however i do not know about the speeds. If you have any ideas on how i can do this let me know