> I am now considering converting the other two 120mm to exhaust and replacing the > "defective" on the side panel, configured as intake as mounted below the > graphics-card. > The second position on the side-panel is above the graphics-card but almost directly > opposite the CPU. Intake or exhaust for this one ?
You always want a high performance fan on the side panel of your case to be internal, so it blows colder air on the north/southbridge as well as other components depending how big the fan actually is.
the fan on your CPU heatsink plus fans on rear of the case will be your exhaust that moves hot air out of the case.
If you can mount a 200mm that pulls a lot of air and is quiet you will see a hell of a difference.
If you wanna go to the extreme then replace everything in your tower with Scythe and remove the heatsink from your GeForce GT430. Clean with isopropyl alcohol and apply quality Thermal Compound. You will see at least a reduction of 20C and possibly more depending. I cleaned a GTX 480 and the difference was over 40C made a huge difference of the heat factor inside my case.