Hardware Energy Efficient Hardware Investigated

How green are green products? We evaluate the benefits, or lack of them, in new "low power" and "energy efficient" hardware to see what makes the biggest difference to the power drawn from your wall socket.



http://www.bit-tech.net/hardware/pcs/2010/02/24/energy-efficient-hardware-investigated/1

 

nevermind missed the AMD cpus on the first page :>

 

One note about AMD - they undervolt very well, and default voltages selected by BIOS is in most cases very high. My X4 620 had a default voltage around 1.35V, yet my undervolting stopped at 1.12V (real, 1.1V in BIOS).

 

I may have my physics wrong, but (from the first page) if a particular product uses 50 per cent more power, but it's also twice as fast (100 per cent) at completing the task at hand, then doesn't this mean this is 33 per cent more efficient, not 50?.

 

For this article, Efficiency = Speed/Power (electrical efficiency is actually [effective energy]/[power consumed]. I assume that [effective energy] is proportional to speed.)

Letting a represent speed and b power,
a/b = E
2A/1.5B = 1.33 E

So yes, math error in the article.

 

Any chance we can get some numbers on how much it costs to run a high powered PC per hour vs a low powered PC per hour? That would be pretty cool

 

It depends on how much are you charged by your electrical company. They can't really do it, but perhaps they could do it in their context, that is, the London context.

 

What about GPUs? was really looking forward to that bit... nevermind. The rest was quite interesting. I'm looking forward to more powersaving specials. :0)

 

Just look at the reviews? They have the power consumption charts in each and every review, don't they?

 

This is exactly the sort of article I like reading.

 

For the UK, as a quick and dirty way to estimate things, I use 1 Watt per year = £1.
So, the difference between leaving on a machine all the time drawing 50 Watts and one that draws 75 Watts is roughly £25 per year.

So saving 10 Watts on a machine that you run for 4 hours a day is less that £2 over the course of a year. If this costs you £40 to achieve, you have to have over 20 years of use in order to justify it. The price of electricity almost certainly will go up, but I'm guessing it won't go up enough to justify the cost given the average lifespan of the equipment (whether through redundancy or failure).

Efficiency does not equate to ultimately saving money, leaving the payback time out of equations is misinformation at best.
(NOT having a go a Bit-tech or anyone in particular, it just seems likes it's fashionable within the "Green" industry to use possible savings rather than actual costs)

 

Something fishy there... If product A uses 100W (0.1kW) of power and does 1 unit of work per hour, we can say its efficiency (workrate / power) is 1 / 0.1 = 10 units/kWh. If product B uses 50% more power (150W = 0.15kW) and is twice as fast (2 work units per hour), then its efficiency can be said to be 2 / 0.15 = 13.33 units/kWh, making it 33.3% more efficient, NOT 50% more efficient.

 

EDIT: Fixed!

Good article. I just noticed that my stupid HD4870 consumes over 70 W on idle. Loving how they cut the idle consumption with the HD5-series cards.

EDIT: Also the sound card seemed to draw more power than I thought.

 

Which is something Jezcentral and me have mentioned.

 

Oops, missed that. Sorry old boy

 

We cover GPUs in depth, so I didn't bother

 

E8400+HD4870 -> i5 750 + HD4870 = 190->160W idle power usage
i5 750+HD4870 -> i5 750 + HD5870 = 160->117W idle power usage

It is funny that moving from dual to quad and from less to more powerfull graphics card results in smaller idle power usage.

 

I know AMD isn't as power efficient as Intel but you can still have some fun with reducing power usage. Just keep default CPU clock settings and create smartprofiles in AOD for demanding games. I'm using this(2.8GHz ->3.5GHz) for Crysis, CoD, Fallout 3 and it works like a charm. If only it was possible to turn on/off Cool'n'Quiet feature on-the-fly...

 

But you can reduce power usage with Intel too!

 

If your PC is idle most the time (like if you browse the web, listen to music, etc), then idle power draws are much more important to focus on. Athlon 240e is the clear winner here. It has the lowest idle power draw of any CPU I have seen. It uses LESS THAN 5 W !!! That includes VRM losses so its pretty impressive. http://www.lostcircuits.com/mambo//...task=view&id=70&Itemid=1&limit=1&limitstart=4 "the power numbers are un-adjusted gross input into the motherboard's voltage regulator module and are, therefore, inflated by roughly 30%. meaning that the CPU itself draws somewhere around 3-3.5W power in idle mode"