Analyzing Power Use: 80 Plus Bronze vs. Platinumby Jarred Walton on October 30, 2013 8:40 PM EST
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|
Intel Core i5-4670K
(Quad-core 3.4-3.8GHz, 6MB L3, 22nm, 84W)
|Motherboard||ASRock Z87M PRO4 (mATX)||$135|
Corsair Vengeance 2x8GB DDR3-1866
EVGA GeForce GTX 780 3GB
(2304 CUDA Cores at 967-1020MHz, 6GHz GDDR5)
Sapphire Radeon HD 7750 1GB (Alternative GPU)
(512 Cores at 800MHz, 4.5GHz GDDR5)
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)|
|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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Drumsticks - Wednesday, October 30, 2013 - linkOut of curiosity - why a GTX 780 and 4670k and 16GB RAM, but such a comparatively low end motherboard?
But interesting findings. I didn't think that you could get savings that decent off of it. Good to know!
ArmedandDangerous - Wednesday, October 30, 2013 - linkBecause an expensive motherboard does nothing for performance, and if the friend required help to build a PC, he probably won't ever be opening the casing to mess around with the internals. USB3? Check. PCIE3? Check. That's what most people ever need :)
1Angelreloaded - Thursday, October 31, 2013 - link"Because an expensive motherboard does nothing for performance".....................
Really? and they allow you to post, the Motherboard is the most important selection piece and can either make or break overclocks which is ya know in the performance category otherwise OC champions would just buy a foxxcon 40$ motherboard and be done with it, but in terms of performance and world records the Rampage/maximus boards seem to have the best features and performance for the prices.
Duwelon - Thursday, October 31, 2013 - linkYou're only talking a 5% difference in performance. The money is much better spent on a better cpu or gpu but assuming you are very high end already, sure grt the crazy expensive mb if it makes you feel better. Personally im a fan of Asus Gene boards but i know much cheaper board would do the same thing.
Mr Perfect - Thursday, October 31, 2013 - linkAssuming that someone who needs a PC speced and built for him intends to overclock anything at all.
Hrel - Thursday, October 31, 2013 - linkAnything beyond $150 for a motherboard and your value/dollar ratio drops through the floor. For most people, who just go on facebook and use Word and maybe play some flash games, stability is really all you should be concerned with. $70 to $120 is a reasonable range.
People who spend 200+ dollars on a motherboard are just wasting money. So I really hope the only people who do that have money to waste. Overclocking? Yeah, he used the K CPU, but really you should get the 4570S and save $20 up front then a few bucks a year on electricity.
extide - Thursday, October 31, 2013 - linkYou wont save any money with a S or T series CPU unless you are running it at full load all the time... All of them use the same power at idle... (K series, S, T, plain, etc)
lwatcdr - Tuesday, November 12, 2013 - linkactually he is right. A good quality motherboard is important. A high end motherboard not so much. Most people do not go for extreme over clocking. Lets face it does the average user need a motherboard with LN2 support? If you are only going to run one or two video cards and a mild over-clock and you are good with just about any good name motherboard.
http://www.youtube.com/watch?v=yeuJAOVRoA0 for some testing to drive the point home.
trivor - Friday, July 8, 2016 - linkActually, the days of EXTREME overclocking are long gone. It was at its peak back when an off the shelf Celeron 300 Mhz would overclock to 450 without premium coolers, MB, or PSU. Back before PSU's became affordable most cheap cases came with a cheap PSU and it was prohibitively expensive (if you were on any kind of budget) to replace the PSU with a good like the early PC Power and Cooling PSUs that were over $100.
Rick83 - Thursday, October 31, 2013 - linkAn expensive mother board usually gets decent integrated peripherals, which can the prevent additional spending on a decent NIC and sound card.