If you still have your monitor laying around I would plug it in as a second monitor so you can run task manager, cpuz, and gpuz (or any other monitoring software) so you can verify that your CPU and GPU are operating at the correct clock rates and load levels. I have not heard of an instance where the TV would cause low fps but I know some TVs have a gaming mode which will help to cut down on input lag from your mouse. Try throwing the TV on gaming mode if it has it in the menu and see if it changes anything.