Originally posted by: ^Sniper^
If I use a mobo without one what could it do? I know my bro inlaw used his PC without one for a few years now without any problems.
The main thing plugging all the openings with metal does is to reduce electrical interference to such things as radio and broadcast TV (and portable phones.) You can hear noise on the radio and see junk in the TV picture. Computers kick out a lot of radio frequency electrical noise. Since metal conducts electricty, electromagnetic wave are either reflected or disappated, and so are blocked from going through. The smaller the holes, the higher the frequency the waves have to be before much can get through.
I doubt if the electical interference will be worse than those cases with the plastic sides. Even with the case completely open on mine, the radio is not too bad about ten feet away from the computer. TV is worse.