Undervolting: Thanks for the answers, I found it intersting to read about power cycles and how they wear down the longevity of hardware. As for undervolting, I am positive it wouldn't effect performance of a chip, it just alters the voltage which is needed for the electrons to jump over into another state, or am I wrong?
Cooling: 4x Arctic Twin Turbo Pro and 4x
Arctic VR001 and 4x BeQuiet PWM 120mm and Open Window.
Alternative cooling suggestions are welcome! Water cooling is a bit too expensive for 4 cards for my taste.
Longevity and Thoughts: Greed kills. Keep it from a long time, Stock, Future, Forex, Metals, Options Trader. That's why I will do this "just for fun", like the inventor of Linux once stated. I won't push my GPUs to the max. I will sell them later and I want the new owner to be happy not to be angry at me. I pushed my 5850 to 360 Mhash/s without voltage tweeks and its in the burying ground now.
Invest in yourselfThe four 5850/70 I bought will make me happy a long time, since I will treat them well. 300 Mhash/s max with lowest memory clocks and extreme cooling. 1-2 hours off time a day. I even gave them names.
Mining is just a game and people don't see that easy money NEVER stays with its owner very long. If you want to make money, invest in yourself, go to University, buy a book, heck buy clothes.