It's fairly common now to see desktop computers in cases with large windows cut in the sides. I've always been under the impression that if unshielded, computer equipment will produce a lot of radio frequency interference. Given the ubiquity of cell phones/wireless routers, etc, I can only assume it's not radiating all that much. What I'm interested in is how much power, over the whole RF spectrum, a shielded and unshielded computer system could produce. My desktop has a 900 Watt power supply. If it radiated even 1% of that power, there'd be a huge amount of radio interference in my apartment, wouldn't there?
Well I don't really know. But two ideas to measure (or compare) it. First if you have a 'scope then clip a bit of bus wire on the end of your x10 scope probe and move it around... take off the case, put it near the over head fluorescent lights. If you don't have a 'scope then you can do some with an AM radio. Tune to a blank spot and try and hear the noise as you move it around. (The radio idea comes from here.)
If you look on the chassis you should see the compliance rating class. Class a or b for instance. This will lead you in the right direction to see what the maximum allowed emissions would be for that device class. Most reputable manufacturers do not publish exactly how close to the class limit the product is as that would give the competition too much info.