I’ve been toying around with updating my computer lately, and one of the topics I wanted to look at was the choice of power supply. For the most part, we’ve long since moved beyond the days where power supplies that cost under $60 are garbage. There are plenty of decent power supplies available, particularly if you don’t mind taking a step down from the latest and greatest in terms of efficiency. Anyway, I was helping a friend put together a new PC the other day and it got me curious.

First, let’s start with the system build he put together, with some input from me. Note that many of the parts were selected based on price and availability on Amazon.com, as that’s where he wanted to purchase the parts (with his Amazon Prime account). In some cases, prices have changed since the purchase a week ago, so shop around as needed. Also note that he used a GTX 780, but I’ve also run some power use tests with just the iGPU as well as with a low-end Radeon HD 7750.

Custom-Built Intel Haswell PC
Component Description Price
Processor Intel Core i5-4670K
(Quad-core 3.4-3.8GHz, 6MB L3, 22nm, 84W)
Motherboard ASRock Z87M PRO4 (mATX) $135
Memory Corsair Vengeance 2x8GB DDR3-1866
(9-10-9-27, CMY16GX3M2A1866C9)
NVIDIA Graphics EVGA GeForce GTX 780 3GB
(2304 CUDA Cores at 967-1020MHz, 6GHz GDDR5)
AMD Graphics Sapphire Radeon HD 7750 1GB (Alternative GPU)
(512 Cores at 800MHz, 4.5GHz GDDR5)
Integrated Graphics Intel HD Graphics 4600
(20 EUs at 350-1200MHz)
SSD Corsair Neutron 256GB $187
HDD Western Digital 2TB Mainstream (WDBH2D0020HNC) $80
Optical Drive ASUS 24X DVDRW SATA (DRW-24B1ST) $22
Case Silverstone PS07B (mATX) $79
Power Supply Antec EA-450 Platinum (450W) $70
Power Supply Cooler Master GX-450 (450W Bronze) (Alternative) $49
Operating System Windows 7 Home Premium 64-bit (OEM) $89
Total Price (not including tax or shipping, with GTX 780 and Platinum PSU) $1592

Now I’m not equipped to tell you about the quality of voltage regulation, ripple, or anything like that, but I happened to have a 450W 80 Plus Bronze PSU that I could use as a comparison point, so I asked if I could take some quick measurements once the system was put together. He agreed, and I ran through a few typical scenarios, summarized in the table below. (Note that I had to use a Molex to 8-pin PEG power adapter in order to run the GTX 780 on the old Thermaltake PSU; everything worked, but that wouldn’t be a solution I’d be comfortable with long-term.)

Bronze vs. Platinum System Power Draw (Kill-A-Watt)
Test Load Thermaltake
Litepower 450W
Antec EA-450
EarthWatts Platinum
24/7 Yearly Savings
iGPU – Idle 34 27 61.4 kWh (~$7.68)
iGPU – Cinebench Single-Core 63 55 70.1 kWh (~$8.76)
iGPU – Cinebench Multi-Core 96 86 87.7 kWh (~$10.96)
iGPU – Cinebench OpenGL 103 92 96.4 kWh (~$12.05)
AMD 7750 – Idle 45 38 61.4 kWh (~$7.68)
AMD 7750 – 3DMark 131 121 87.7 kWh (~$10.96)
NVIDIA 780 – Idle 48 41 61.4 kWh (~$7.68)
NVIDIA 780 – 3DMark 348 325 201.6 kWh (~$25.20)

For power costs, we’re looking at the worst-case scenario of leaving a system on 24/7, which really isn’t realistic unless you’re talking about a server. For a typical PC that’s on eight hours a day, using the US national average price for electricity ($0.125 per kWh), we’re looking at electrical savings of anywhere from $2.56 to $8.40 per year. That may not seem like much, but considering any decent power supply should last five years and you’re looking at $12.80 to $42 in savings. That’s for a $21 difference in upfront costs, which is much smaller than what we’ve seen in the past for the most efficient power supplies – and note that the price difference tends to grow substantially when you’re shopping for 800-1200W PSUs, though that’s perhaps a topic for another day.

For a system that mostly sits idle, you won’t quite break even by going with an 80 Plus Platinum power supply. However, if there’s a graphics card installed and you do a moderate amount of gaming you should eventually come out ahead. More extreme use cases (e.g. 24/7 Folding@Home) start to rapidly recover the initial investment in a quality power supply, and when you consider the reduced heat and noise that comes with having a more efficient PSU, it’s definitely a worthwhile upgrade. Not all 80 Plus Platinum power supplies are created equal, of course, but generally speaking the electronics and engineering required to get that certification also come with a higher level of quality than what you’ll find in lower efficiency PSUs.

As far as the above system build is concerned, I like most of the component selections, but I’m not totally sold on the case. The Silverstone PS07B looks nice enough, but getting all of the wires connected can be a bit difficult at times. The SSD location on the bottom in particular is a bit of a pain, and the power supply location at the top has some silliness to go with it. The PSU location appears designed to work with the PSU upside down (i.e. fan facing upwards and drawing in fresh air), but the manual for the case notes that if you have a PSU with a 120mm or larger fan, they recommend installing it with the fan facing down. I'm not sure that I've ever seen a PSU with a fan smaller than 120mm where you have ventilation through the bottom, but whatever. If you follow the manual’s instructions, that means the ventilation holes in the top of the case along with the magnetic dust filter are completely pointless. I ignored the instructions and installed the power supply in the most sensible manner for the case, but my advice is to look at some of the other good mATX cases.

The Silverstone PS07B isn’t a bad case, but it’s not perfect either, and for the price I think you can do better. (Apologies to my friend for his taste in cases….) For mATX, I’d at least give the BitFenix Prodigy M or Corsair’s Obsidian 350D a look. If you want a larger case, there are tons of options to sort through, depending on what you're after. Other changes you might consider include sticking with 8GB RAM (2x4GB) initially, going with a midrange GPU like a GeForce GTX 770 or Radeon R9 280X, and there are quite a few motherboard options to consider as well. The i5-4670K still strikes a nice balance between price and performance, and with a bit of overclocking you can stretch its legs a bit further.

Anyway, that’s my little two-for-one special for the day: a quick look at the difference in power use you can expect from 80 Plus Bronze vs. Platinum (obviously 80 Plus Silver and Gold will be closer in power use, but they’re also closer in price), along with a list of parts that I’ve recently used in a friend’s PC. If you have any recommendations or complaints with the build, sound off in the comments.

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  • Not This Guy - Thursday, October 31, 2013 - link

    The Z87M PRO4 is a "comparatively low end motherboard". It has standard chipset features, standard audio, the CPU power system is basic and it has none of the high end features which you see in most reviews here (PLX, extra IO, water block on chipset, etc.).

    Asrock is just another motherboard company. Many of their products are made in the same foxcon like plants which all the others are. He said nothing about Asrock, you did.

    But seeing as you brought Asrock up, some of their products are gimmicks. I bought the Z87 Professional for five features features, all of them turned out to be non functional or useless.

    FAN-Tastic Tuning does not work.
    HDMI-IN does not work.
    Sniper Key and "Fatal1ty Mouse Port" does not work.
    Windows OC Tweaker barely works (their BIOS is excellent).
    The Audio location mini HUD in their advertising material does not exist (and is now removed from their website).

    On the plus side, Good Night LED works great, you just have to reset your computer to enable (kind of defeating the purpose).

    Maybe it's my fault for attaching decent kit. And I'm saying nothing about the PRO4. But Asrock is no where near where it needs to be in terms of execution to be considered high end.
  • ruzveh - Thursday, October 31, 2013 - link

    ram has nothing to do with high end and low end MDB
  • 1Angelreloaded - Thursday, October 31, 2013 - link

    Yeah I agree, those compo are really good yet the Motherboard is the basic building block and needs to be good to get decent features, your computer is only as fast as its slowest equivalent part, if the mobo is third rate then the system will be.
  • MadMan007 - Wednesday, October 30, 2013 - link

    I think 80plus gold is currently where the price:performance (in this case, performance being power efficiency) sweet spot lies. There are often sales on good platinum units (I'm looking at you, Seasonic 660XP2), but otherwise solid gold (unintended joke ;)) units like Seasonic G series are always a good value.
  • Grandal - Wednesday, October 30, 2013 - link

    "and for larger ATX builds I’m quite partial to Corsair’s Obsidian 350D"

    I thought the 350D was a mATX case... roomy, but still for mATX boards.
  • JarredWalton - Thursday, October 31, 2013 - link

    oops... fixed. Was thinking of the larger Obsidian I think.
  • meacupla - Wednesday, October 30, 2013 - link

    seeing as PSUs can be used for a while, like 7+ years, it would seem like a $30 more for gold or platinum will pay for itself in about 5 years, which is pretty good.
  • Rick83 - Thursday, October 31, 2013 - link

    This depends largely on the longevity of said power supplies. Had a Seasonic in 24/7 behind a UPS, and it died on me after around 4 years or so. 7+ sounds highly optimistic to me, I don't know of any power supply that has lasted this long, and I've bought many, mid- to high-end supplies from a number of vendors.
  • fokka - Wednesday, October 30, 2013 - link

    thanks for the article, those are the little things i'm often curious about!

    seems, at least to me, that a more efficient psu should be worth the money for most builds, not only because it saves a couple bucks of electicity, but also for the already mentioned advantages in heat dissipation, noise and general quality, stability and (hopefully) longevity. also i could imagine that "higher tier" PSUs tend to come with longer warranties, which would be another plus.
  • eek2121 - Wednesday, October 30, 2013 - link

    Your friend appears to have overspent (no offense.) I just put together 3 machines (at work no less)...Core i7 4770s, 16 gb ram, 250 gb samsung 840 evos, radeon 7950s, case, 600 watt ps, dvd rw, etc. $1300 shipped from amazon (each, after tax).

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