[BCAB] The often forgotten cost of running a PC

Mark Kirkham mark.kirkham at tiscali.co.uk
Sun Jun 24 13:26:24 BST 2012

Hi all,

When you consider that most desktop PCs have a power supply rated at between 
400 and 800 watts, it's perhaps not surprising that the running costs can be 

Even in sleep mode, some of the internal fans will still be running and, of 
course, the electronics will still be awake enough to sense any signal to 

Conventional LCD screens are also quite power hungry - typically around 60 
watts, so turning off the screen when not in use is advantageous.

The increasing popularity of laptop computers and tablets has led to the 
development of processors and screens with much lower power requirements. 
LED screens are coming down in price and, before long, will become the norm.

My own feeling is that conventional desktop computers with large system 
boxes and significant cooling requirements will soon be obsolete. The Apple 
iMac is a step in this direction, with all the power of a conventional 
computer but an LED screen, efficient processors and all the electronic 
gubbins contained within the monitor case. The total power consumption is 
around 60 watts max, and about 1 watt when hibernated. There are internal 
fans, but these activate only in response to temperature rise if the 
computer is working hard. Normally the machine is silent and the fans are 


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