I recently ordered all the components for a new desktop system to replace my old, dying computer. I wanted to have a really quiet desktop, so I got a case rated for being quiet and opted to try a closed-system CPU water cooling kit (Antec Kuhler H2O 620) that was on sale for a very good price over the Thanksgiving weekend. Most of my components are still in transit, but I became somewhat worried when a friend mentioned that abandoning air cooling units can result in heat buildup inside the case due to heat generated by the video card and other components such as RAM, the northbridge, MOSFETs and voltage regulators radiating heat that the CPU fan would normally at least keep circulating around so it doesn't build up in localized areas.
Is this a realistic problem? What other precautions should I take to remove heat from other components? Adding more case fans seems like it would get really noisy. Are there quiet alternatives?