Case cooling: Any point adding case fans when....

... i have my case off? I thinking there is no point adding fans when my case if off, cause the hot air will just diffuse out of the case. or would fans blowing in the case and sucking out help the cause a little?

It is a fairly hot British summer day, my room temp is 29C. I am running my system (Athlon (Thunderbird) 1200 ) with one side panel off a mid tower case.
I have a Silverado on the cpu, plus two case fans (front inlet and rear exhaust) which each move 46cfm.

My system (motherboard) temp was 32C and cpu temp was 47C (100% cpu load).

As an experiment I disconnected the power to both case fans, within fifteen minutes my temperatures had increased to: system 39C and cpu 53C.

Whilst my system is considerably quieter without the case fans running I conclude that unassisted convection cooling is not very effective.

You would think it would'nt matter with the side open but I have an 80mm and 92mm outake on top of my case and my case is open on the side and when I flick on the fans my CPU temp drops 3c hard to beleive. This is my theory: everybody knows heat rises, so I think the hot air just hangs out on the top of the case and only slowly disapate only to be replaced by more hot air. When I flick on the fans voila no more hang out.

Mama always said "There's no such thing as a stupid question if you don't know the answer"