There's always some radiation emitted from any sort of electrical device. EMF or something I can't recall my Physics very well. But its only from high voltage devices where this is a problem. Which is mainly why they don't build houses under those nice big power lines, or near power pylons.
You might think your comp runs at 12V, but remember that your PSU takes in power at 240V, which isn't really astronomical, but if you're like me, kinda lifeless sitting in front of a comp almost every waking hour, then you'd take it into account.
tom_pearson said:
Hmm I'm not too sure I agree with you when you say its best to have an equal amount of fans (in and out). IMO this doesn't seem right, I personally think the best way to cool a case is to have two intake fans which are GOOD air movers. then as many as possible near for example the power supply, the CPU, and the PCI/AGP cards. If you blow cool air onto for example the CPU the warm air will escape into the ambient areas, and in turn increase the case temperature (very slightly, but enough). If you fill the case with cool air, then drag it across the necessary areas, there will be no heat dissipation into surrounding areas. It will just be sucked OUT.
I didn't say best to have equal amounts, its a suggestion if you don't want to worry about how the air flows and all that. If you can direct your air around the case perfectly, having no stagnant pockets, or having hot air going where you don't want it to, well, you can have all intake fans, no problem since only the hottest air will be expelled naturally from the pressure imbalance.
Also, yes, if you don't mind the case temperature going up a little, no exhaust fans will do fine. But beware of other components which may not be getting that cool air, HDDs being the main target if there's no front fans. My comp with 3 fans doesn't run a front fan, but I've self designed heatsinks for my solo HDD, and so far its running pretty cool, so I'm not in a hurry to install one.
Also, most PSU have 1-2 fans, and they're exhale fans (most, if not all). Raising your case temp will increase the running temp of your PSU, which lowers the total watts it can handle. Not a big problem, unless you're running a generic PSU with just enough Watts to go around.
Most cases also do not have fans which blow directly into the AGP (nor can you install them) so your AGP might overheat too. Best way to overcome this is to install one of those PCI exhale fans (there you go, one exhale fan). Good on you if your case has a fan blowing at that direction, mine doesn't.
So if you're reading this and going "I can't be stuffed looking into all this", install some exhaust fans. If you've got all the time in the world (like me), go ahead, and slowly monitor that airflow (coloured gasses work pretty wel for these purposes, the same stuff they use to check a car's aerodinamics). Or maybe use what I do: just run the comp, stress every part so it produces the most heat, shut it down, open it up, and stick my hand at various components and try to guess where could do with some extra airflow. Helps to keep the side panel ready to be opened.....