Door mux op zondag 2 september 2012 23:44 - Reacties (78)

Categorie: Fluffy2, 20W all-in-one, Views: 266.599

Mux' laboratory

The need for lower power consumption

How to build a low power computer

It needs to be completely silent. No fans.

Total power consumption including screen <20W

It will become an all-in-one computer

It needs to be altogether wireless. I want to be able to pick her up and walk away with her.

The monitor has to be IPS.

Processors : Both Intel and AMD make comparably power-efficient processors.

: Both Intel and AMD make comparably power-efficient processors. Motherboards : Intel and low-end to midrange MSI motherboards are the way to go here. Avoid Gigabyte and Asus if you're going for efficiency.

: Intel and low-end to midrange MSI motherboards are the way to go here. Avoid Gigabyte and Asus if you're going for efficiency. Memory : Do whatever you like. I've investigated this a couple of weeks ago.

: Do whatever you like. I've investigated this a couple of weeks ago. SSDs : Avoid LSI/Sandforce and JMicron. Make sure you put as much often-requested data on your SSD so that any hard drive in your system may spin down.

: Avoid LSI/Sandforce and JMicron. Make sure you put as much often-requested data on your SSD so that any hard drive in your system may spin down. Hard disks : Never use RAID, it has no use and has a very negative effect on your power consumption. Use as little hard drives as possible, preferably of the highest necessary capacity. One 3TB disk is more power efficient than two 1TB disks. If not more than 1TB of space is needed, go for 2.5" models.

: Never use RAID, it has no use and has a very negative effect on your power consumption. Use as little hard drives as possible, preferably of the highest necessary capacity. One 3TB disk is more power efficient than two 1TB disks. If not more than 1TB of space is needed, go for 2.5" models. GPU: If at all possible, use an integrated graphics chip, not discrete graphics cards. Most modern-day game titles, as well as basically all graphics-intensive programs can be run on IGPs nowadays at acceptable frame rates. Only use discrete graphics if they're absolutely necessary.

Advanced techniques

So, what is the end result?

Conclusion

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I'm also on the twitters! @EfficientElec What I want for my computers isand. That last term means that I want them to achieve maximal performance while using minimal power, money and space on my desk. To accomplish this, I do not hesitate to solder the most essential parts right off the motherboard to see if that helps in it’s power consumpion. Also, to help both myself and others, I often design special electronics to make personal computers more efficient. Since I am one of the few people willing to go this far for the cause, there is not much information available about the risks and gains of these methods. With this blog, I am trying to educate people in a vast range of relevant subjects: From low power computer displays to power supply technology , an explanation of power factor correction and the worklogs of my previous low power builds: Dennis (20W Core 2 duo), the award-winning Fikki3 (8.3W Core i3) and Floppy2 (9.5W NAS), the last of which does not yet have its own blog entry. Also, I like to give my computers names so everyone knows which one I am talking about. For instance, today we are going to discuss Fluffy2, the successor of Fluffy, formerly my main computer.In contrast to my earlier builds, Fluffy2 is going to be an all-in-one computer: this means the computer is going to be built into the monitor. It will also be a high-end computer: The parts are among the fastest currently available, it has as much RAM as will fit in it and the monitor will be of the IPS variety. The case is a custom design with an integrated and quite massive passive cooler, and features a battery so Fluffy2 can keep working in case of a power outage or, well, if I want to take her to another room.Computers are extremely important in our modern daily life. Not just your own computer, but the computers at your office, the ones in the grocery stores, the datacenters that allow me to share this blog with you and all the computers we need to, for example, buy something online. All these computers have something in common: they are overdimensioned for their use. What I am trying to say is: None of those computers are working at. A computer that is working at full power all the time, would be seen as slow or noisy and would be quickly replaced. The logical consequence is most actual (overdimensioned) computers are idle a lot of their time (70% idle time in datacenters and over 95% in home computers). In that idle time, the computer still uses power, but it is often impossible to turn it off to save on the electricity bill. It turns out the total power used while the computer is idle, is often more than the total power used while the computer is actually doing useful work!Just as a quick example: right now, my computer is almost idle: My CPU-usage is less than 5%. Can I turn my computer off? Of course not, I am writing a blog! So what I want, is for the computer to use as little power as possible while it is idling. This is what I have been concentrating on for the last few years and it has yielded some nice results. Here is the idle power consumption of my computers over the past couple of years:So, how does one go about making the most efficient computer in the world? The first thing you need to do is to specifywhat you want from your computer. A lot of people would say ‘I want a fast computer that will last me 3 or 4 years’. But what is fast? And do you really mean that 3 years, or do you secretly already know you replace your PC every other year? Maybe instead you want to use it much longer, or give it to your little niece when it becomes outdated? You need to be as concrete as possible in your specification. This is a proper foundation to build on, so you won’t be tempted to change something in the foundations later on (which could collapse your whole building - to stretch this metaphor).For instance, my own specifications for Fluffy2 were:In a future blog, I will explain how these specifications led to the components I chose. Anyway: with your own specifications, you can check which components match your requirements. The key to your succes is: make sure your componentsmeet your specifications. Do not go above, do not go lower either. In my experience, at this point you will have a pretty short list of suitable components.With this short list in hand you can make targeted low-power choices:And now for the special Mux sauce: what do I do that makes my computers so power efficient? Apart from well thought-out specifications and of course a vested interest in low power computer components (which is something that simply requires a lot of reading and experience) I also look further than the component level in computers. I look at the components thatPC components: the chips on the motherboard, the discrete components in a power supply. This type of information is usually not freely available, so the only way to get to know exactly how a motherboard or power supply is formed from its components is to probe and trace out everything on the boards. This results in diagrams like this showing all components on my motherboard (DQ77KB) and where those components get their power from:This is not all she wrote. Once I know how power is distributed and what components actually use power, I need to measure exactly how much power is used by what. So I need to measure the currents and voltages going through all the above. Once I know this, it is simply a matter of trying to undervolt or power down components starting from the one using the most power, all the way down to the components using the least power. In order to help me visualize which components should receive priority efficiency treatment, I make things called proportional diagrams where components that use a lot of power are really big, while power-sipping components are really small. Like this:This is super useful. It allows me to get an idea for how much leeway I still have. For instance, this diagram shows that the processor uses a bit over 1.5W of power when the computer is idle. I know for a fact that this is about as low as I can get CPU power consumption, it is a hard wall. So clearly, I won't be able to gain anything there. This puts an upper limit to the amount of power I can still save by modifying other circuits, and gives me a realistic goal to aim for. For instance, with this information in hand I can safely say that it will be extremely hard to get down to 5.0W total system power consumption.Now, there is another interesting part to that last graphic: the brown block on top of everything called 'conversion losses'. As you may know, computers use a power supply to convert mains AC power to a voltage that is suitable for computers: 12V, 5V and 3.3V. But this is not the only 'power supply' in your computer: there are many very small power supplies in your computer that for instance convert the 12V from your power supply into about 1V for the CPU. These converters are colloquially known as VRMs or voltage regulator modules and as you may guess already: these suckers are not perfect. Every time you convert electrical power, you will lose some of that power as heat. As it turns out, a whole lot of it. Where and how these power losses occur can be visualized using a so-called Sankey diagram, like this:In this type of diagram, the power that goes into the computer 'flows down' from above and losses incurred in power conversion are 'diverted' to the side. Only the green arrows pointing down actually eventually go into the chips in your computer to do useful stuff. If you gather up all those greem arrows, it turns out that of those 5.9 watts of mains power, only a measly 3.66W is actually used, the rest is ejected as waste heat! And what's more depressing: for computers this is actually very good. Any non-power-optimized computer, which is pretty much all other computers, use about 30W of power when idling. This is largely due to conversion losses. Only a tiny fraction actually gets used for useful activity. Even on systems using those fancy 80+ Gold or Platinum rated power supplies.Using the above knowledge and helpful visualizations, it was actually not that hard for me to pinpoint where I needed to modify my computer to make it as efficient as possible. It only took about a month of working in my free time to complete the task. The result?In this graph I recorded the power consumption before (red) and after (green) I performed my power optimizations on Fluffy2. Note - None of these optimizations impacted performance or functionality in any way!Even though Fluffy2 was already one of the most power-efficient configurations you can buy today I still managed to chip off almost half of the idle and low-load power consumption. And the power savings are universal: even at full load, Fluffy2 used a quarter less power than before. Compared to a typical modern-day desktop which uses about 30W idle and 150W under full-load conditions, the savings are even more dramatic. I've compared my results to other people who make super-efficient computers their hobby and I think I can safely say that I have made the world's most power-efficient desktop computer by a comfortable margin!Now, to conclude, here are a couple of nice pictures of all the modifications I've done to the motherboard. Not all of them are especially obvious, but they're nice pictures nonetheless.I hope you liked this chapter in the megaproject that is Fluffy2. But wait, this is only the beginning. This chapter is just an introduction with the fruits of my labor. In a couple of upcoming blogs I will try my best to explain in a more in-depth fashion what I did and how I did it. Also, I will publish blogs on the other aspects of Fluffy2: the UPS (battery module), true power off module and of course the case design, the last of which is already featured in a video blog . Stay tuned and if you'd like to support this project and help me do awesome power-saving work for the PC community, you can find a donation link below.