Open case vs. closed case with fans

Get a case with case fans and keep the panels on. Otherwise you essentially have hot, stagnant air sitting in the case and you will more than likely have overheating problems.

I have a friend who refuses to put his panels on his case and his video card overheats and throttles itself resulting in horrible performance. You need to keep that hot air moving out of the case, the fans on the components aren't enough to bring in cool air from outside.

Of course my friend went the overkill route and got a window air conditioner unit for his room and just keeps it at like 65F...

Open case does nothing for airflow through the system. A closed case with the right fans in the right places moves air thoughout the system with a positive flow of cool air in, hot air out. Much better cooling than a case sitting there simply open. If open was better, cases would be made with a wire mesh or screen on the side instead of a solid piece of metal.