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Efficient Computer - 12VDC or 240VAC

(18 posts) (7 voices)

Started 3 years ago by Doug
Latest reply from CNCandy

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Doug
Member

Power Efficient Desktop Computer.

After reading some recent home power audits from ATA members and articles in Renew, I thought I should check the power usage of my home PCs. Sure enough, the PC in my study was operating at 150-200watts and that doesn't include the monitor! It was just an ordinary desktop about 2 years old.

Since then, armed with the PowerMate energy meter, multimeter, a large selection of parts (both old and new) and many hours of testing, I have built-up two PCs that are considerably more efficient, as well as better performing:

1. A 240VAC powered PC that typically operates at < 50watts watts.
2. A 12VDC (solar) powered PC that typically operates at < 40watts watts.

That

Posted Sunday 8 Mar 2009 @ 2:18:56 am from IP #
moz
Member

I've looked at this, but settled on a much less technically challenging approach... I bought a second hand laptop for $500 and keep my big desktop for when I'm working. The laptop draws about 30W minimum and 50W with the screen brightness at max. Over time I'm transferring more and more of what I do to the laptop, so the desktop is only getting a few hours a week. Unfortunately I do actually need it for some things so I can't just ditch it.

The desktop is pretty new and with all the power saving features enabled draws about 150W, plus 50W for the 20" monitor and 70W for the 30" monitor. At full blast I'm still over 300W total, but I rarely use it that way these days, usually leaving it in power-save mode (which slows down the CPU, RAM and video cards).

In terms of cheap, simple solutions I think a laptop is definitely the way to go.

Posted Wednesday 18 Mar 2009 @ 11:31:13 am from IP #
rockabye
Member

I opted for a macmini G4 computer which uses about 20-25W, the higher figure is when burning or playing a DVD. I use a 24" Acer LCD monitor on the text brightness setting which consumes about 30W. When I walk away from it I turn off the monitor or if I intend to be away for longer than 10 min I set it to sleep mode which drops the power use to about 3W.

I initially bought the mac to avoid the high maintenance, high stress ownership of Windows based pc's and the low power consumption turned out to be a bonus. Zero problems since switching some years ago. It runs on my small battery backed solar array and inverter 24/7 along with the adsl modem and VOIP adaptors.

The latest MacMini is still only $949 edu price for a dual core intel with OS and software.

Posted Monday 23 Mar 2009 @ 4:47:11 am from IP #
Doug
Member

COST, DESIGN & SPECIFICATIONS

Design principles that I noted for power savings in a desktop PC:

- Use a new, cheap motherboard with integrated graphics (all-in-one). PCI graphics cards waste power! And unless you are a serious gamer, they are not needed.
- Use an efficient CPU. The Intel 45nm Pentium Dual Core or Core 2 Duo chips are good. Celeron 400 series are also fine. (Pentium 4s and early dual-core Pentiums are dreadfull. Even Celerons before the 400 series are poor). I'll test an Intel Atom next...
- Select an efficient power supply. Typically, the lower the power rating the better. I tested lots of old supplies until I found some that were OK. Efficiency varied greatly, between 50% and 80% efficient. Getting an "80 PLUS" certified power supply is great but more costly.
- Enable sleep in your power settings (with S3 suspend mode set in BIOS). I set mine to sleep after 15min and wake by hitting the keyboard (takes only 10seconds)

Cost and specifications:

1. A 240VAC powered PC that typically operates at < 50watts watts.

The parts cost less than $500 but make for a sweet performing machine.

- Intel 2.5Ghz E5200 Dual Core 45nm CPU
- Gigabyte (or ASUS) Intel G31 chipset motherboard with integrated graphics
- 2GB RAM (2 x 1GB DDR2) in dual-channel mode
- 500GB SATA2 HDD Western Digital Caviar Green Power
- DVD Burner
- I tested 6 old power supplies with my "Powermate" meter until I found the most efficient (it still wastes about 30% of the power just in the power supply!

2. A 12VDC (solar) powered PC that typically operates at < 40watts watts.

The specification is the same as one above apart from the power supply. I used a 12DC ATX power supply from Jaycar. It is way more efficient than the regular 240VAC power supplies, saving about 20%. It also uses much less power when in sleep mode (2.1watts v's 3.8watts)

Power Measurements for 12VDC PC:
- Idle at desktop - 36watts
- Watching video over the internet - 38watts
- 100% system load using Prime95 Torture Test - 64watts (you never get this in real usage)
- Sleep - 2.1watts
- Off - 0.13watts

My next project will be to use the new Intel Atom dual core CPU...

You can email me with any questions or tips faithfull-farmer@bigpond.com

Posted Friday 27 Mar 2009 @ 12:12:15 pm from IP #
rockabye
Member

One thing I forgot to mention is how critical the brightness setting on LCD monitors is. On the text setting as I mentioned it measures about 30Watts. However on the graphics setting it rises to about 75Watts.

So when it comes to low power "computing", the monitor can be the big power user. Even though my macmini is a miser when it comes power use I still use an Acer netbook , about 10watts, for a lot of my day to day activities. So the laptop approach is definitely a good idea in my view.

Posted Sunday 29 Mar 2009 @ 6:19:40 am from IP #
rockabye
Member

I've been looking into a conversion to 12V for an Apple IMAC G4 computer and it seems doable. These were the most classic design macs ever built IMO and the one I am experimenting with uses 50watts including the 15" screen. The will also run the current latest MAC operating system with 512mb of ram so you don't have to put up with old software. No need for antivrusetc and rock solid reliability.

They are still available on ebay from time to time and 17" and 20" ersions were also produced.

http://en.wikipedia.org/wiki/IMac_G4

Anyone else played with these?

Posted Friday 8 May 2009 @ 9:05:17 am from IP #
rockabye
Member

Latest iMac and more importantly a new super efficient Macmini has been released. The entire lifecycle has been considered in its manufacture as well. I'm biased of course and mine runs on solar anyway.

http://www.apple.com/au/macmini/environment.html

Posted Wednesday 21 Oct 2009 @ 12:14:40 am from IP #
Eco
Member

I know you are looking primarily at desktop computers however notebook computers are usually pretty efficient - they have to be for battery life. My Acer notebook use 30 to 37 Watts (measuring power supply Wattage). And I am sure that there are many notebooks better than that (my battery life is dreadful).

Posted Wednesday 21 Oct 2009 @ 4:01:37 am from IP #
rockabye
Member

I agree that notebooks are the ideal if screen size isn't an issue. The majority of my websurfing and forums etc is on my Acer One which uses about 15 watts.

But for reading lots of pdf files in full A4 two page spread which I do a lot of to save paper the macmini and 24" lcd does the job very well.

Posted Wednesday 21 Oct 2009 @ 4:56:02 am from IP #
CNCandy
Member

Hi All, I must wade in here (wade, wade, wade) as I build energy efficient systems and more to the point high end workstations. I will tell you right now 300 watts for a desktop PC of only a couple of years old means that you have something terribly inefficient in there probably and AMD chip of some kind and you are running a high end gaming rig.

As a comparison the new Intel Core i7 chip is around 130watt idle in a system but it is orders of magnitude faster than anything out there. I'm building a couple tonight and will let you know later what numbers my power meter generates.

- My System -
I have an Intel Core 2 Duo E6550 which like yours is a maybe 2-3 years old.
2x WD RE2-GP ( Green Power ) which is a lower wattage drive (5 vs 9) in a RAID 1 array
9600GT Card which in draws around 95watts in Vista and 140 when gaming.
My LG 22" LCD is about 40watts
I also have a 380w 80+ PSU...

My advice is use an Intel Atom be it a Single or Dual Core. The dual core is just 2 chips on the one board(2x4watts), it has on board video the 950GMA which is woeful for any form of gaming other that flash based games - but it works. You can use an old PCI graphics card if you want some form of graphics. The 945 chipset does slurp power so it's not as good as it could be.

The atom in a desktop is around the same power as a notebook (25-40w) and if you team that with a green drive you'll be around 35watts. Netbooks with a Z series Atom are far lower as they idle at 0.1w!

Instead of a hard drive you could use a solid state drive most of which draw around 0.1watt when active - and are about 150times faster than a hard drive, the speed here being the latency or seek time.

I would alter dougs build above to use a Zotac 610i (www.zotac.com.au)which has an onboard GF7050, the Caviar Green is the best choice or the Samsung ECO Green series is another option. You could also use the Zotac ION chipset which is an ATOM chip teamed with a 9400GT card built in so you can play HD video.

Must get back to my builds,

Posted Wednesday 21 Oct 2009 @ 8:49:32 am from IP #
franks
Member

The netbooks (Asus Eee PC) with the atom chip sounds very interesting for 12v DC remote area powering.
Im tempted to use one at my bush block weekender got a 12v PV RAPS system aprox 1200w/h per day capacity, power compsumption of the netbook is under 30 watts, all I need is cheap wireless internat at my location

Posted Wednesday 21 Oct 2009 @ 9:47:23 am from IP #
rockabye
Member

The newest thing on the block apart from the Iphone are going to be smartbooks. Similar to the netbooks but able to run 10 hours per charge. There has been a massive uptake of netbooks worldwide so it is likely the smartbooks will follow. Being released this year I believe.

It's great to be able to walk into a library or airport and check your mail or book accommodation or just sit in my lounge chair and surf the net while watching tv.

http://en.wikipedia.org/wiki/Smartbook

Posted Wednesday 21 Oct 2009 @ 9:58:39 pm from IP #
CNCandy
Member

Franks, There is an desktop EEE PC (called a Net Top) which can attach to a larger monitor. There is also the hard to find but usually bundled with ASUS 16" Widescreen which gobbles a mere 19-34w if that is of interest. It floats between those values but usually 19w in Windows.

http://www.asus.com/product.aspx?P_ID=0NACweKzmwTOsIZJ - spec says < 35watt
If you go back a couple of menu's in the top there is a more modern rounded bezel design.
I use Asus because of the compliance with the European ROHS, and the innovative design. Like the ASUS Notebook with a bamboo (renewable) chassis.

Posted Thursday 22 Oct 2009 @ 9:02:16 pm from IP #
Greenozi
Member

Re Smart books. I just have one of the latest and more expensive Sony PRS-700 and to be fair I am quite disappointed. If not used (charged) for a week battery is flat. Reading is difficult, software and files compatibility just awful. What the point the book that is never going to work unless first charged for couple hours.
Summarizing.
The whole idea of electronic book (even magazines online - I can envision our ReNew in few years) is fantastic but at this moment manufactures capitalized this enthusiasm (Kindle and Sony) to the worst experience possible. Lack of color, poor battery performance (could be solved by attaching solar cell on top cover), unfair price (for same amount in excess of $500 you can buy descent laptop or netbook for much better quality experience). Even distribution eBooks quite unfair. Now you buy paper book and is always yours. Purchased electronic files may disappear from faulty memory stick and expensive book is gone. It should be electronic ownership available. Once title purchased online should be registered in your name in central database and always available for you to access. Then we can create own private library without risk of losing everything with faulty hard disk or memory stick. Especially that electronic version is not much cheaper that paper copy.

Posted Thursday 22 Oct 2009 @ 11:00:10 pm from IP #
rockabye
Member

Greenozi,

The 'smartbooks' I am referring to are very low energy laptops like the ACER netbook I use. They are full functional mini laptops but with more efficient processors usually running Unix or Linux operating systems. Not quite the same as an electronic book.

Posted Thursday 22 Oct 2009 @ 11:09:12 pm from IP #
Greenozi
Member

sorry rockabye, I am little behind with this latest progress in laptops. But this two should merge into one one day. The most basic laptop to access internet and read or play.

Posted Thursday 22 Oct 2009 @ 11:23:32 pm from IP #
Greenozi
Member

As I can see future of laptop/ mobile phones, Ebooks there is always the same irresolvable conflict. Too small screen- difficult to read too big and less portable and power hungry. So where is the future for all this, which one wins?
None.
Future is in electronic glasses.
Same as we are using today for reading or against sun but displaying picture directly to your retina.
Keyboard could be virtual or none (read your skin potentials or brain waves)
Advantages:
-microscopically low power consumption to power color lasers
-virtual picture displayed on top of your view
-You can have and uses everywhere in bus, train, car always present without setting up laptop or iphone
-unlimited resolution (limited by your own retina only)
-use to enhance also your vision at night at distance, at different spectrum i.e gamma ray?

Posted Friday 23 Oct 2009 @ 1:02:47 am from IP #
CNCandy
Member

One of the people in my HSA course had an Sony e-book and it was pretty snazzy device having an sd card slot, the sony card thingy and a mini usb. So there's always a way to save your e-book to transfer to another device.

The Intel Atom Netbook Tablet I recently got for the assessments is the new dual core Z500 series which the fountain of all human knowledge (Wikipedia) says uses 0.01watt when idle. I would tend to agree as I left it on standby the other night and it used a mere 3% battery and the onboard SSD is only 0.1w when active!

Posted Sunday 25 Oct 2009 @ 8:55:20 am from IP #

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