There's two ways you have to look at a computer to analyze this. Firstly as an electronic device (most of it) and as an electro-mechanical device (mainly the hard drive).
For an electronic device, the *only* appreciable wear-and-tear it gets is during power-up while it is coming to its normal temperature. The chips begin warming up, causing the circuit board to flex due to uneven heating. Even though the amount of flexure is small, it still represents bending the traces (wires) on the board...and you know what happens to a piece of wire if you bend it back and forth enough. Once the temperature has stabalized on the board, there's no appreciable wear and tear.....no flexure, and electrons moving around on wires don't wear out the wire at all. Ergo, for things with circuit boards, you want to minimize power-down/power-up cycles to minimize wear and tear.
For hard drives, it's not much more complicated. They can and do wear out, as all mechanical devices do. So the question is, what causes it to wear out faster? If the system is idle, this boils down to two main things....the motor that is spinning the platters, and the bearings supporting the spindle. Modern hard drives have sealed bearings filled with a long life lubricant. Like any bearing lubricant, it is thicker when it's cold and thinner when it's at operating temperature. Thus, if the machine is at room temperature and you power up, there is more resistance in the bearings causing the platter motor to work harder (causing wear on both the bearings and the platter motor). Next you have to consider the platter motor itself. It should be obvious to anyone who has endured a high school physics class that it is *much* harder for a motor to spin up the platters from a dead stop than it is to simply keep them spinning once they're already at speed. So, again, the most wear and tear happens at power-up time.
It should be clear and obvious that leaving your system on 24/7 is easier on the system than powering it down each night. However, this fact is mitigated by the insane MTBF (mean time before failure) ratings of modern hardware. Whether the extra wear and tear of power-cycling the equipment daily is significant enough to affect you over the life of the system can be debated, but is closely akin to rolling dice. It might break, it might not.
As far as energy consumption, know that a modern PC doesn't burn much power at all....a couple of amps max. If you have a CRT monitor, however, that's what's sucking power. The system I'm using to write this consumes about 2A, the CRT burns about 4A. So if energy usage is an issue to you, my advice is to leave the system on, but turn off the monitor at night. Or, if your monitor is EnergyStar compliant, quit using a screen saver and set your computer to simply power off the monitor after about 20-30 mins of non-use.
|
