[krazy]

For the time being, I unplug my pump and rad fans manually when I shut my machine down (which is not very often). Once I get my new tower and finally am able to build everything inside of it, I will have a somewhat extravagant setup that allows me to set the pump to either be on no matter what, off no matter what (using a momentary-type switch for safety) or be controlled by a relay on the PSU like most people do. The rad fans will also be powered independently of the main PSU and there will be a switch to set them to constantly on or PSU relay controlled. This way it will be easy to fill and bleed the system, as well as do quick checks by cycling the pump off and back on, etc.

I don't see any advantage to leaving the pump running constantly when the computer is powered down. Every pump has a lifespan, and each rotation just counts up on the odometer. I wouldn't mind setting up a circuit that would keep my pump and fans running for 20 or 30 seconds after a power down just to suck any remaining heat out of the machine instead of just letting it sit there and cook with no ventilation.