Build Your Own Low-Wattage PC with Three Simple Design Rules

Kannon Yamada 10-04-2017

You don’t need a laptop to get an energy-efficient computer. In 2017, building a power-efficient PC requires knowing just three tips.


Three kinds of component and configuration options lead to a power-efficient build. In order of importance:

  • A high-efficiency power supply.
  • Components with low power consumption.
  • Configuring your BIOS/UEFI to use less power.

Power Supply

Power supplies don’t convert from wall AC current to DC without a great deal of loss in power. The average power supply converts at 70% efficiency, meaning 30% wasted energy. However, two kinds of power supplies convert at over 90% efficiency: PicoPSUs and 80+ Platinum (and the slightly better Titanium) rated power supplies. When choosing a build, either option presents a good choice. However, PicoPSUs cap out at around 200-watts. On the other hand, Platinum and Titanium rated PSUs cost a fortune – the cheapest Titanium PSU goes for about $140.

It’s also important to note that power supply efficiencies vary depending on load. Most supplies provide their greatest efficiency at around 50% maximum load. Therefore, you should use a load calculator before choosing a power supply’s wattage. Whatever your requirements are, our list of the best PSUs will help you discover what your options are.


Low-Power Components

Aside from the power supply, five other components can make a difference in the amount power consumed by your system: the CPU, RAM, storage drive, motherboard, and case. You can find lower power options for every one of those categories.


CPU: The most power-efficient motherboards come with CPUs that have been soldered to the board. Unfortunately, that means if either the board or the CPU goes bad, the entire unit must be discarded. Personally, I prefer using lower-power CPUs combined with small form factor mini-ITX motherboards.

Build Your Own Low-Wattage PC with Three Simple Design Rules build pc cpu

RAM: RAM comes with a voltage rating that varies between 1.5 and 1.25 (or possibly even lower). Unfortunately, according to Tom’s Hardware, that translates to around 1-watt at idle and 4-watts at maximum load. If you’re looking to save power, you’re better off throwing your money into a better power supply.

Storage drive: Solid State Drives (what’s an SSD?) use substantially less power than regular hard disk drives. SSDs add amazing performance while consuming a tiny fraction of the wattage of a regular platter hard disk drive. The wattage savings depend on how much you write or read data. According to Quora, however, the power saved adds up.



Motherboard: The only motherboard (that I know of) designed specifically for low-power operation is MSI’s ECO line. ECO motherboards can selectively disable unused components. With all the overhead trimmed out, an ECO board consumes around 40% the power of an ATX motherboard.

Build Your Own Low-Wattage PC with Three Simple Design Rules msi eco motherboard
Image credit: MSI

Case/Chassis/Heatsink: Overall, a case isn’t going to save you much energy or provide efficiency gains. However, the fewer fans in your chassis, the less power consumed. Under full load, a standard 90mm fan can consume around 5-watts of power. Most PCs use around three fans. However, a few fanless cases exist, such as the HD-Plex H1.s and Akasa’s Euler. Altogether, a completely fanless system might reduce power consumption by around 15-watts at load. Check our our roundup of the best PC cases to find a case that suits your needs. (Also, consider thermal paste to keep the processor cool.)


Graphics Processing Unit (optional): In case you’re also thinking of getting a graphics card, look no further than NVidia. Dollar-per-dollar, the most efficient card is the Nvidia GeForce 1050Ti (or 1050).

BIOS/UEFI Settings

There are a number of settings located in the BIOS (and its next-generation replacement, UEFI) that aren’t enabled by default that can have a noticeable impact on power consumption. Simply enabling the various power states on Intel boards (C1E and EIST) can reduce power consumption. You will want to enable them if they’re available on your motherboard. Some BIOS/UEFIs use colloquial language to enable lower power states, such as “eco-mode” or “low power mode”. Enable these, if available.

Desktop manufacturers tend to leave these settings off for performance purposes. Higher frequencies tend to generate snappier performance. However, most users won’t notice the difference and you should definitely consider turning on your power-saving features.

Another BIOS/UEFI setting that can be turned on is EuP2013, which is the European standard for idle state power consumption. If enabled, the computer will use no more than half a watt of power while powered off. However, more modern implementations use almost no power when shut off.


Tom’s Hardware published an excellent review of the various power-saving BIOS settings.

Undervolting and Underclocking

Don’t confuse the two. Undervolting How Undervolting Decreases Heat & Increases Battery Life Would you believe that many computers and smartphones can run cooler and consume less power? A trick exists, called undervolting, which can increase your CPU's efficiency with few drawbacks. If performed right, devices generally produce... Read More and underclocking save power in completely different ways. Undervolting reduces the amount of voltage delivered to the processor. If done properly, undervolting has no downside. Done incorrectly, it causes instability. Unfortunately, only expensive, high-end motherboards offer this feature.

Underclocking, on the other hand, doesn’t improve your processor’s efficiency. It only decreases its maximum frequency. In general, you are better off not underclocking, unless there is a good reason.

Build 1: $700-1000 Deluxe

In 2017, both AMD and Intel manufacture highly efficient, high-performance processors. In the 65-watt range, Intel offers the Core i7-6700 for $303, whereas AMD’s Ryzen 7 1700 runs for $320. It’s not clear which processor possesses the advantage in power consumption, though. However, Legit Reviews did a detailed analysis of Ryzen 7’s power draw vs the Core i7-6700K and it appears that Ryzen comes out ahead. Also note that Intel’s latest series of processor, Kaby Lake, produces almost the exact same performance as its older generation Skylake processors (Core i7-7700).

Because of the motherboard options available, though, the build presented here uses Intel (despite some serious thermal design flaws Two Ways to Cool Down Your Defective Overheating Intel CPU Looking to purchase a Haswell or Ivy Bridge Intel CPU? A secret may change your mind. According to bloggers, Intel recently got caught using thermal paste on its CPUs and lying about it – the... Read More ). Also note that Intel’s T and S series CPUs use between 35 and 65 watts. On a higher end build, I would prefer getting a Core i7-6700T or a BGA board, but these are hard to find and aren’t as performant as a slightly more power-hungry chip.

This particular build won’t knock any socks off. In fact, it remains relatively mid-range in terms of gaming and CPU performance. Even so, it provides a highly efficient computing experience, with only a marginal markup. While you can make this build totally fanless, it’s good to at least have some airflow, which in this is provided by the power supply’s very slow moving fan. The case includes a couple of fans, which you don’t really need.

The Nvidia 1050Ti is among the more efficient GPUs around, although efficiency is pretty much a continuum. Picking the most efficient gaming GPU 3 Affordable AMD APU-Powered DIY Computers That You Can Build The Accelerated Processing Unit, or "APU", design integrates a graphics processing unit onto the same die as the CPU, resulting in a faster, more efficient hybrid design. For those of you seeking to build a... Read More depends on your needs.

  • CPU: Intel Core i7-6700 — $293 via Amazon;
  • Hard Drive: OCZ Trion 150 240GB SSD — $70 via Amazon;
  • Motherboard: MSI ECO H110M LGA 1151 MicroATX — $59 via Amazon;
  • GPU: EVGA GeForce GTX 1060 6GB — $235 via Amazon
  • Power Supply: Rosewill 550W — $90 via Amazon;
  • RAM: Viper Elite Series 2 x 8GB — $98 via Amazon;
  • Heat Sink: NoFan CR-80EH — $47.80 via Amazon
  • Case: Xion microATX — $23 via Amazon;
  • Total: $915.80

Price accurate at time of writing.

Build Your Own Low-Wattage PC with Three Simple Design Rules xion performance matx case

Build 2: $400-699 Midrange

For lower-cost builds, Intel’s 65-watt Core i5-6400 CPU offers solid, low-wattage performance. It doesn’t offer Hyperthreading What Is Hyper-Threading? [Technology Explained] Read More , but it does maximize energy efficiency. On the downside, I stuck in an 80+ Gold supply, rather than a Platinum-rated unit.

  • CPU: Intel Core i5-6400 (65-watt) — $176.90 via SuperBiiz;
  • Hard Drive: OCZ Trion 150 240GB SSD — $70 via Amazon;
  • GPU: EVGA GeForce GTX 1050Ti Mini 4GB GDDR5 — $132 via SuperBiiz;
  • Power supply: Seasonic SSP-450RT 450-watt — $60 via SuperBiiz;
  • Motherboard: MSI ECO H110M LGA 1151 MicroATX — $59 via Amazon;
  • RAM: Ballistix Sport LT 8GB Kit (2x4GB) — $59 via Amazon;
  • Case: Xion MicroATX — $23 via Amazon;
  • Total: $579.90

Price accurate at time of writing.

Build Your Own Low-Wattage PC with Three Simple Design Rules seasonic spp 450rt

Build 3: Below ~$200 Low End

On lower end machines, I once recommend AMD’s APU technology. However, Intel’s latest Celeron and Pentium processors outperform them in most ways — for not much more. For example, the N3150 processor inside of the MSI ECO Mini-ITX motherboard draws 6-watts while also allowing users to shut off non-essential motherboard features for additional power savings.

For AMD-equipped examples, I put together three sample APU builds 3 Affordable AMD APU-Powered DIY Computers That You Can Build The Accelerated Processing Unit, or "APU", design integrates a graphics processing unit onto the same die as the CPU, resulting in a faster, more efficient hybrid design. For those of you seeking to build a... Read More , in case you want other configuration options. However, Intel right now offers the best power efficiency for low end builds.

  • CPU + Motherboard: MSI N3150I ECO mini-ITX — $75 via Amazon;
  • Hard Drive: ADATA SU800 128GB SSD — $52.88 via OutletPC;
  • RAM: Patriot Signature 4GB (1 x 4GB) SODIMM — $23 via Amazon;
  • Case + Power Supply: Antec ISK110 — $48 via Fry’s Electronics;
  • Total: $198.88

Price accurate at time of writing.

Build Your Own Low-Wattage PC with Three Simple Design Rules antec isk 110 670x310



Building your own highly efficient desktop computer doesn’t take a lot of work or money — it just requires specialized parts, proper BIOS configuration, and a high-efficiency power supply. For a selection of fanless, high-efficiency PCs, check out FanlessTech’s entry-level, mid-range and high-level rundown of builds. Or if you’re looking for silent, fanless machines, drop by our run-down of prebuilt eco-friendly PCs Eco-Friendly Computing 101: Buy or Build Silent and Green PCs Computer fans clog with dust, make horrible noises and waste energy. Why put up with that when consumers can go silent and green? A huge number of options popped up for setting up highly efficient... Read More .

Related topics: Green Technology, PSU.

Affiliate Disclosure: By buying the products we recommend, you help keep the site alive. Read more.

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  1. kEN
    October 1, 2017 at 12:16 am

    I hate windows 10 but like you build. What parts would I need compatible with windows 7?

  2. Howard Lam
    September 29, 2017 at 1:43 pm

    Actually GTX 1080 is much more efficient than GTX1050Ti especially after downclocking to run at 90 TDP.

    Looking at Folding@home score, gtx1070 is rated at 5.6k Points per day/Watt while the 1050ti achieved only 1.9k PPD/Watt.

  3. Caleb
    December 15, 2015 at 4:23 pm

    I'm curious: did you ever test to see what wattage these PCs idle at? I'm currently trying to upgrade to a 24/7 desktop/server by choosing low-watt components, but I'm not sure what wattage goal is realistic.

    • Kannon Yamada
      December 15, 2015 at 5:41 pm

      With a large number of attached hard drives you might have a different idle state than my own -- but on a fanless Haswell system, with low-voltage components, by idle rate is around 12 watts. It can be much lower for a system that uses Braswell or other low power systems.

  4. Anonymous
    June 17, 2015 at 11:51 pm

    Hi there,

    I am interested in building one of these, but the information is now a little out of date with regards to sourcing current components that are compatible.

    Would you mind making an update for 2015?

    Thanks :)

    • Kannon Yamada
      June 23, 2015 at 3:30 am

      Good idea. Braswell is probably one of the better low-end, low-power systems out there. And the Taiwanese mobo makers are now starting to release products in this range. I'm going to wait until mid summer before getting started on this one, though.

  5. southleft
    December 19, 2014 at 4:54 am

    Here in the USA we just built an HTPC based on an ASRock Q1900-ITX motherboard, a single 4GB stick of low-voltage DDR3-1333 RAM, an old Kingston 64GB SSD running Windows 8.1 Pro with Media Center, and a 2TB WD hard drive for recording TV shows. We housed it in a leftover Antec mid-tower case.

    The motherboard has an embedded Intel Celeron J1900 quad-core cpu @ 2.0GHz. Yes - an actual quad-core Celeron! But, the best part is that it's passively cooled and has a maximum power consumption of 10 watts (typically it runs at around 4 watts). So, it's silent, incredibly efficient and it records and plays 1080p video perfectly. It's also fine for internet, e-mail, casual games, light office work, etc. The WD 2TB hard drive is allowed to sleep except when recording or playing back so, overall, this system is so frugal on power that we just leave it on all the time.

    Using leftover items from previous systems such as the Antec case, a copy of Win 8.1, a stick of memory and a small capacity SSD kept our building cost to a minimum ($75 for the motherboard/cpu combo + $84 for the WD 2TB drive).

    We could have used a free version of Linux instead of Windows if necessary. In future we might splurge on one of those very small ITX cases to house the system, and that would allow us to mount it right on the back of the TV. Of course, that would require an external hard drive case resting nearby somewhere.

    • Kannon Yamada
      December 15, 2015 at 5:43 pm

      Super late response, but I ended up buying the ASRock Q1900-ITX for my own server and found it was not Linux compatible. ASRock's official line is that they don't support Linux for the Q1900-ITX, I think because they added a third party chipset to support the extra 2 SATA ports. I think with some tweaking Linux will work, but it doesn't out the box.

  6. BonesDT
    April 26, 2014 at 12:40 pm

    Since when is $425.90 below $399?

    • Kannon Y
      May 2, 2014 at 5:04 am

      Prices went up slightly. I'll correct it right away, thanks for your help!

    April 2, 2014 at 2:34 pm

    Hi Kannon, great article. I appreciate your mentioning in your builds.

    Just a couple of things. The Realan E-i5 makes a great substitute for the E-K3i which we haven't been carrying for a while.

    For build #3 I recommend the 120W AC adapter. You'll also need a low-profile CPU cooler since the stock AMD CPU cooler won't fit. Also, the A8-3850 is a 100W TDP CPU which I would not recommend for any of the Realan e-mini cases due to heat. The A6-6400K would be a better choice or when it is available the A8-7600 tuned to 45W and the Gigabyte A88X mini-ITX motherboard.

    If anyone has any questions on building with Realan e-mini cases, feel free to contact me (Doug) at

    Thanks again Kannon!

    • Kannon Y
      April 3, 2014 at 10:53 am

      Whoa, that was a series of pretty serious errors - it appears that somehow the wrong APU got added. It was supposed to be a Trinity quad-core or a lower end Richland dual-core, which I think was out of stock by the time this article finally published. Somehow a Llano APU got added. Hopefully no one purchased the FM1 CPU for the FM2 motherboard. I really appreciate you notifying me of the mistake!

      What's really awful about this is that I ordered the Ek3i from you (and I LOVE the case) and neglected to mention that it requires a low-profile cooler. I needed to proof-read that final entry more closely.

      I ended up pairing it with a ECS KBN-I/2100, passively-cooled motherboard and it's fantastic.

      I also have a A10-5800K(100watts) - I tested it using Kill-a-Watt and at average load (with an HD6670 in dual graphics mode) it uses around 120 watts. At max load it uses around 190watts. Would a 84-watt PSU provide enough power for a 65-watt APU, without a discrete card?

      Apologies for asking so many questions of you - but is there any reason you stopped carrying the Eik3? It's an amazing case. Most Realan cases are so well put together. It's hard understanding why they're not a bigger force in the HTPC market in the states.

  8. Shodam
    November 5, 2013 at 7:49 pm

    Since you brought HTPC use into the conversation, I'm wondering why the "little black boxes" made by folks like Western Digital (WDTV) and ASUS (Oplay) scenario wasn't brought into play. Those boxes are all fanless, stream 1080 with a mass of supported formats, are tiny and have at least some internet streaming function built in.

    All at a sub$150 US price tag.

    When paired with a networkable external drive, flash drive or even connected to a server, you have the potential for ultra small, low wattage HTPC duties at a lower cost than your budget build.

    I've put this system in place for various family members looking to duplicate a HTPC build I did several years ago. If those had existed then, I could have easily saved myself over $1000 dollars on my build, piles of energy use and simplified my space to accomplish the same tasks.

  9. Andrew R
    November 5, 2013 at 11:46 am

    I wanted a low power enviro-friendlier PC, but did not have time or experience to put it together in the time-frame I had. I opted for a mini PC and use it as my everyday desk top. It performs well and is much more efficient than my older PC's. I notice this particularly on how much longer the UPS lasts in a power outage. (even though I am using 2 monitors).

    • Kannon Y
      November 5, 2013 at 6:40 pm

      You chose well Andrew. That particular design uses embedded components and likely a ball-grid-array CPU connector style, meaning it's much lower wattage than a traditional desktop CPU.

      It also uses an offboard, passively cooled power supply - these are often in the high 80% of efficiencies, if not higher. While it does uses a spin up hard disk, this is mitigated by the fact it's a 2.5" drive, which means it probably uses a lot less energy than a 3.5". Very nice, thanks for sharing!

  10. shinrakurisu
    November 5, 2013 at 8:29 am

    Your timing on this article (and your link to past experiments) is impeccable, Mr. Yamada. I've spent a good deal of last week entertaining the idea of a low budget, casual/indie gaming/htpc build.

    I've been on reddit, hard forum, pc part picker, lifehacker, toms hardware, anandtech and then out of nowhere...a makeuseof article on the very things I wanted to know!


    • Kannon Y
      November 5, 2013 at 6:13 pm

      Thank you for the comment!

      May I ask what your target price is? I feel the optimal build cost for an APU is between $200 and $500. Anything more than that and one should consider an Intel build using a discrete GPU.

      If you just want an HTPC/indie gaming platform, I would target $300-350 and leave room open for expansion. Although if you want to create a highly efficient and cheap build, this limits expansion. One of the reasons I suggest the Realan series of case is that it has the efficient PicoPSU built into the frame. All the cables can reach without extension or tweaking. And it costs only about $10 to 20 more than you would pay for a lower quality case.

      Regarding quiet - APUs without proper configuration will produce quite a bit of noise. AMD's stock CPU fan isn't designed with silence in mind, unfortunately. There are compact and slow-moving CPU fans available, but these add around $40-50 to the total price of the computer. I'm using the Gemini II on my APU rig. Very quiet. But there are better fans available, such as Noctua's L9 series.

      I did a rundown of indie game bundles, by the way, that you may have some interest in checking out:


      Let me know if you need additional tips. I can write a guide.

  11. Mihir Patkar
    November 5, 2013 at 6:18 am

    Great article, Kannon! I've actually been looking to build a quiet machine for an HTPC. Any recommendations on that front?

    Will the low-end machine above get the job done for FullHD MKVs?

  12. likefunbutnot
    November 4, 2013 at 7:42 pm

    Depending on your specific needs, you might be able to get away with using either a dedicated RDP/VNC/X client device (Wyse terminals sell for peanuts on Ebay) or use a dedicated STB that happens to have available RDP/VNC client software. You're really only pushing the power use off on some other machine, but it makes a lot of sense to use a 5W client with an ARM CPU and enough horsepower to display 1080p rather than an ~80W x86 system if you just need a remote display for doing work and already have a serious desktop computer on your LAN someplace.

    Gamers are SOL on that, but gaming and power saving are generally not ever going to be a winning combination. On the other hand, a decent network connection can manage perfectly acceptable video playback over a remote desktop-type session.

    • Kannon Y
      November 5, 2013 at 4:50 am

      Awesome comment.

      I've been considering running off an ARM desktop and then using a VNC client to mirror a Windows desktop whenever I needed that sort of software. The hardware isn't quite there yet, though, unless you're talking about the Nvidia Shield. Which is a pretty fantastic device.

      I'm waiting on Qualcomm to develop a big.LITTLE chip with an optimized scheduler, though.

    • likefunbutnot
      November 5, 2013 at 5:20 pm

      @Kannon Y: The hardware is ABSOLUTELY there. Pushing 1080P video is mostly a function of having decent back-end hardware and a good network connection, but if I can interact with an RDP session as if I were sitting in front of the console on a boring old 1GHz dual core Tegra 2, it's only going to get easier.