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Energy saving PC

Update: October 2008.

The parts for this PC were bought in 2004/2005. Processor and motherboard are not available any more in the shops.
There are more new, energy efficient processors and mother boards available now, but still they are not often used to save energy. You still will have to make an nerdy effort yourself, like switching off not used cores in a multi-core processor. Dynamic throttling (changing processor speed) and dynamic Vcore (variable voltage) of the processor still are not wide spread, you still need to tame your PC yourself.
 
The good news: My prototype inspired a new startup company to produce the TurtleStep PC.

Want to to see the results without all the nerd-talk? Scroll to the bottom!
 
Planning to buy a new PC, because I needed more power for editing images and audio, I soon found out a new PC would easily use twice the power of my current PC. This would also be the case while doing my daily work, which does not demand much speed. The cause for this is that the ICT-industry simply is not serious about energy saving (yet). So I set out to build my own energy saving PC. Not only to save energy and money, but also to show even an amateur like me can do this.

Aim: at least 2 speeds:



Athlon Mp

Processor:
AMD Mobile Athlon XP-M 2600+


AMD specs:

Athlon XP 2600+ Barton
1917 MHz @ 166 MHz FSB, 11.5x multiplier, 1.65 Vcore, 68.3 watt

Mobile Athlon XP-M 2600+ Barton
2000 MHz @ 133 MHz FSB, 15x multiplier, 1.45 Vcore, 45 watt

Energy use at 2000 MHz, PC as a whole:


                              idle      stress
Normal Athlon XP 1.65 Vcore:  99 watt   123 watt

Mobile Athlon XP 1.45 Vcore:  84 watt   102 watt

Saving:                       15 watt    21 watt

In upper ranges inefficiency rises: 1.75 -> 1.775 Vcore (0.025 change) = 5 watt more
(Many processors don't run at optimum efficiency speed, but highest stable speed ...)



Nordbridge

Motherboard:
Abit NF7-S v2












Other parts




Issues down the road

Things I had to find out the hard way ...


Results

CPU 1 = Comparable to my old 1997 Pentium 2 PC at 266 MHz, which uses 48-77 watt

CPU 2 = Energy eff. PC at 5x100 = 500 MHz speed: 50-53, with CpuIdle: 48-50 watt

CPU 3 = Energy eff. PC at 11x191 = 2101 MHz speed: 106-138, with CpuIdle: 93-116 watt

CPU 4 = Intel Pentium 4 processor at 3000 MHz in a game PC: 170-237 watt
(The 'A-brand shop equivalent' of my energy efficient PC).
 
So the energy use of my new PC at 500 MHz is generally always well below that of my old 266 MHz PC. And again demonstrates speed is not only about megahertzes: The responsiveness of the new PC is off the scale, even at 'only' 500 MHz, compared to the old 266 MHz PC. Much faster and much more memory, much faster hard disk access and transfers, much faster data-transport by the motherboard and the fast videocard all have a major role in making the new PC perform so much better.
I can do much more with less energy, that's progress ;-)

Compared to the PC from the shop at the same speed, it saves 45-51% electricity. In the 'light daily work' mode it saves over 70%. With real laptop technology the savings could be even better.
 
Note that both my old and my energy saving PC's have 2 hard disks. With only one harddisk (like the A-brand PC compared here) energy use would even be 6-8 watts lower.
Update October 2008: In the near future I will replace the two hard disks with one bigger hard disk and make my daily backup on a USB hard disk, which is switched off the rest of the day.
 
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