The Cost of Running Your PC

by Christoph Katzer on 11/14/2008 3:00 AM EST
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  • walk2k - Tuesday, November 18, 2008 - link

    If you're curious to find out what your system actually uses, for about you can buy a P3 "Kill-a-Watt" power meter from Amazon for about $24. This is a doo-hicky that plugs into the power outlet, and then you plug whatever you want to measure into that. I've personally found it very enlightening.

    My current PC uses about 120 watts idle in XP, up to about 150 watts when actually doing stuff (cpu slightly loaded, HDD churning). Then in games with the GPU loaded it uses about 200 watts. I only managed to get it to 233 watts when running both a cpu stress test (Orthos) and GPU benchmark (3dmark06) at the same time.

    I'm in CA and pay about 13 cents/Kilowatt/hour so theoretically if I left my system on 24/7 (I don't) at idle it would cost me about $11 per month. In reality I use my computer about 5 hours a day, with about half games (200 watts) and half just surfing, etc (120 watts) so say average 160 watts x 8 hours x $.13 x 30 days = $5 per month.
  • glynor - Tuesday, November 18, 2008 - link

    The prices listed on the EIA website that you used to generate all these numbers (for the US) are based only on the price residential customers pay for energy generation, and do not include the cents per KWH charge that all customers must pay for transmission. Even though I simply take the standard offer from my utility company (like most people), my actual price is roughly DOUBLE what the EIA lists as the average for my state.

    Look at your bill. Make sure to add the totals for both Generation (Supply) and Transmission. These are billed separately.

    With that in mind, most of the example totals reported in this article, and certainly all the comparisons to "Europeans paying more" are completely bogus!
  • Maiyr - Tuesday, November 18, 2008 - link

    Why bother with all of this just to figure out how much it costs to run your system ? Surely someone must have thought of just plugging in a Kill-A-Watt Electricity Usage Monitor....

    Maiyr
  • gochichi - Tuesday, November 18, 2008 - link

    I would look for better efficiency rating for the following reasons (in this order):
    1) I speculate the product is a higher quality product.
    2) Inefficiencies turn into waste heat, cooler is more stable, more pleasant, and longer lasting (speculations)
    3) I guess maybe saving a couple of bucks on my bill, but it's definitely not as important to me as just knowing that a have a "pimp" power supply.

    What this article does make me want to do is try to figure out what sleep modes best suit my desktop computers (particularly my seldom used older desktop). Cold booting is inconvenient and I have been careless about finding a reliable sleep mode. I think the trick is to go S1, I just switched my main computer from S3 to S1 and it really helps stability and responsiveness.

    I wonder how running laptops does in terms of power efficiency. There's got to be a ton of inefficiency caused by charging and discharging the batteries all the time. The design circling around a portable battery also makes it pretty power thrifty at the same time. Just curious as to how it actually pans out. Laptops have typically been more robust in sleep mode too though.

    Random comment: Is it just me or have software updates gotten beyond the ridiculous point? Seems like they are not only often, but they are in your face... like it's OK to interrupt what you're up to a few times a week to get the update "right now"... I mean forcefully.


  • bob11d50 - Sunday, November 16, 2008 - link

    I just wanted to justify my purchases of energy efficient computer components.

    The reason for this was about 3 years ago I had 9 people living in my house and the power company was on a teared system. I got up to the fourth tear where power was up to $0.85 KWH. This was in San Jose California with PG&E as the power company.

    I got my server down to 77 WATS with a EE Athlon at idle from about 230 with my dual Opteron. All measurements were using the Kill-A-Watt.


  • sheh - Saturday, November 15, 2008 - link

    I was always under the impression your total power readings were at the outlet, and so included the efficiency loss of the PSU. If that wasn't the case, how do you measure total power draw from within the computer?
  • Christoph Katzer - Sunday, November 16, 2008 - link

    Motherboard, system, graphics-reviews got readings from the wall. power supplies are loaded with a programmable load, so we can easily calculate the losses. You can know the power draw from mobos, gfx and so on when measuring the power distribution inside of the case which isn't difficult if you know which cable powers which part of which component ;)
  • bigsnyder - Saturday, November 15, 2008 - link

    What kind of case is that in the picture?
  • Christoph Katzer - Sunday, November 16, 2008 - link

    Silverstone TJ10
  • GimpyOne - Saturday, November 15, 2008 - link

    Not sure about Europe, but here in the US, the cost of "electricity" is only about half the bill. Once they tack on things like Fuel Cost charges, Energy improvement riders, resource adjustments, etc. you double the actual bill (literally).

    So more appropriate cost saving could actually be closer to 2x what is here.
  • 7Enigma - Monday, November 17, 2008 - link

    I think you mean 1/2. Most of these charges are regardless of actual power used. Things like transmission charges, local/state taxes, "improvement" fees all will be the same each month whether you draw 100kW or 10. Where the savings *can* become more than stated is if your local utility uses a stepped price plan. That is to say you pay $X up to 500kWh's, then a higher rate after that level. This is how my bill is done unfortunately. I was under the impression there was some sort of peak hour price and another price for off-peak (as many places have). This can be taken advantage of by doing high energy tasks like the washer/dryer/dishwasher/ect. at night or early in the morning where you may be paying anywhere from 20-50% less for the same amount of power. With flat rate stepped plan you cannot benefit from using off-peak, and in general wind up paying more for your energy since they don't care if you used that 1000wh at 3am or 5pm.

    Everyone should check their bill statement and look to see how they are being charged. If you have a stepped plan like mine you may benefit more from being more energy conscious than if you have typical peak/off-peak pricing.
  • raWill - Saturday, November 15, 2008 - link

    Infact I have thought about it - I'm so glad I got rid of my 8800GTS, what a pointless consumer of power when all I do is surf the net 90% of the my computer is on.

    Even worse is people that leave thier sli systems on whilst downloading torrents, etc.

    By managing my standby power sources (turning them off every night before bed) and only downloading torrents and such whilst I am using the computer I saved about $20 a month in electricity. I live on my own too!
  • mongo lloyd - Friday, November 14, 2008 - link

    PSU efficiency will always be higher in Europe than the US due to 240VAC. I didn't see you adjusting for this, but granted, I only skimmed the article because my electricity bill is baked into my rent.
  • ggordonliddy - Friday, November 14, 2008 - link

    It's okay, Osama will pay for it. I mean Hussein. I mean Obama.
  • atm - Friday, November 14, 2008 - link

    Thanks for posting this article. Without the monitoring equipment at home, I was in the dark about true system power draw.
  • ytsejam02 - Friday, November 14, 2008 - link

    I am all for saving energy. I have 3 computers in my house (laptop, desktop, and htpc), and both the htpc and desktop are running 45W cpu's with the Western Digital Green Power drives, and using the onboard graphics and sound. I run all the programs I need with that, so I hope I'm doing something right with these configurations, and that they are low power consumption.

    Now my problem. How much energy would be required to recycle a constant PSU turnover? I'm sure it wouldn't be constant, but I've no idea what it would cost, so I'm thinking in generalities at the moment.

    Either way, I'm guessing that would eat into a large part of the overall global energy problem.
  • IcePickFreak - Friday, November 14, 2008 - link

    I'm waiting for PC Power & Cooling to release their 10MW fusion reactor PSU. No longer will I be tethered to a power outlet or subjected to power outages.

    As a bonus, think of the m4D 9AM1nG 5ki11z I'll have when I sprout a third arm!
  • Carnildo - Monday, November 17, 2008 - link

    I'm afraid you'll be disappointed, then. Fusion reactors don't cause mutations.
  • chenedwa - Friday, November 14, 2008 - link

    Could anyone estimate the cost of a typical laptop setup? Many will keep the laptop's adapter plugged-in 24/7 regardless of whether the computer is attached.
  • strikeback03 - Friday, November 14, 2008 - link

    Using a Kill-A-Watt for measurement, my T43 with 15" S-IPS screen, Pentium M 1.86, ATi X300 graphics, 2GB RAM, and 100GB 7200RPM HDD uses 11W at idle with the lid closed, 18-21W at idle with the screen on (depending on brightness) and about 40W under load. Other laptop reviews on the site here offer power consumption numbers as well.
  • JarredWalton - Friday, November 14, 2008 - link

    If the laptop isn't plugged in, the power brick should use 0W (or at least less than 1W).
  • MadMan007 - Friday, November 14, 2008 - link

    ...and thi quote is the most important one that made me decide it's not economically meaningful to upgrade from a ~75% PSU to an 85% one. When you do these estimates on non-24/7 use the savings plummet quickly.
  • MadMan007 - Friday, November 14, 2008 - link

    Grr...quote window didn't work right, why can't we just use tags?

    Anyway here's the quote:
    "If you only run the system eight hours per day, however, the difference in cost drops off quickly."
  • Nfarce - Friday, November 14, 2008 - link

    "Hopefully we've made it clear that upgrading an existing power supply to a higher efficiency model purely for the power savings doesn't make sense."

    I am not nor have I ever been concerned how much power my PCs use (or my PS3). Compared to other "hobbies" such as street racing, cruising, spending $50/night bar hopping, and other things people get involved with and in trouble over, PC and console gaming at home is cheap and relatively environmentally friendly. Besides, the logic behind spending hundreds on a higher efficiency PS to lower utility bills is about as brilliant as spending $30,000 on a new hybrid Camry to save money on gas. But if it makes you feel better about yourself, hey, it's *your* money.

    However, as we shift to a new administration in the States next year which has already stated it wants to target the coal industry, I might have a change of tune. We will see utilities skyrocket with the green syndrome of progressing to wind farms and solar power that just won't make up for coal fired plants. We already know the environmentalists and other special interest hacks here will poo-poo on nuclear power.

    Talk to me in two years...
  • Griswold - Friday, November 14, 2008 - link

    About time you share our energy pain in europe, then. :P
    You're still not where we are as far as gasoline goes...
  • 7Enigma - Monday, November 17, 2008 - link

    Then blame your government. Your high gas prices are a direct result of high taxes (likely to pay for the universal healthcare), not that we in the US get a better deal.
  • yyrkoon - Friday, November 14, 2008 - link

    Using less power will *always* benefit a household more than anything else concerning saving money where power is the concern. It is also not just a one item deal when trying to figure out how to cut power costs. Refrigerators/deep freezers commonly in most households use more power than anything else. Microwaves, coffee makers, rice cookers, and hair dryers etc can all use more power, but typically run for far less time. Another place to save on power costs would be changing the type of lightning one uses, say from incandescent lighting to LED lighting.

    However, as has been said by many people before in the past, many many times: there is no such thing as a free lunch. Saving power by using a more efficient light as an example is of course going to cost you more money. But also with LED lights you're going to pay a premium for those more efficient lights. So, in the short term, best way to save money is just to turn that item off when not in use. This goes for VCR's, Computers, or whatever does not need to be plugged *right_now*(and yes, most of us should know that most appliances do draw at least some power when off, but still plugged in). Even going completely off grid(meaning you get your power 100% from solar, wind, or multiple other sources) is going to be just like paying your power bill up front, with reoccurring charges for batteries, and maintenance for your equipment. In case of the latter expect to pay tens of thousands of US dollars just for the price of admission.

    Now, as for as strictly Power Supplies are concerned, Yes a more efficient power supply *will* save you money. How much really depends, and there are other factors to consider than "how efficient it *is*'. You need to determine exactly how much power your system will consume, and procure a PSU that is most efficient at that power level. Just because a power supply is 99.9% efficient does not mean it will work well for your given application. Other factors would be longevity, and reliability. Data centers often purchase PSU's where the given system using them only uses 25-40% of that PSU's capacity. This is why current technology is 'trending' towards power supplies with a better/broader power efficiency range(e.g. they are most efficient on the power curve where they are planned to be loaded at). That said, these types of power supplies used by data centers, etc are not of the off the shelf variety(usually).

  • Staples - Friday, November 14, 2008 - link

    There are a ton of people who leave their computers on 24/7 for no good reason. I am a tree hugger and of course I put mine into S3 sleep if I even walk away for more than 10 minutes. Plus, my second computer is very low power because I bought really low power parts for it including one of the most important, integrated video.

    In my main computer, I have an ATI 4850 which sucks a lot of power even being idle and I have a guilty conscious about even using for non gaming needs. Hybrid VGA power state hardly exists now but I am glad it will be coming eventually because powerful video cards sitting idle is one of the biggest wastes of power. Also, I am glad that Vista has Cool and Quiet built in because most people do not even know you need software to make it work (unlike Intel's speed step which works without any software).
  • cyclo - Saturday, November 15, 2008 - link

    This is where nVidia currently has ATI beat. I'm not sure about nVidia's cards on the lower end of the scale but on the GTX 2xx class of cards, they implement a power saving "2D" mode when the GPU is mostly idling (basically when not playing games or videos).

    On my GTX 260, the GPU core downclocks to 301 (from 621), the shader to 602 (from 1295), and the memory to 200 (from 2052) when I am just surfing the web (which is basically "2D" mode). The clocks go up to default as soon as I start playing a video and of course start playing a game. The temps at "2D" mode goes down to 47 C from 54 C in idle "3D" mode (playing a video).

    There is one problem though and I hope nVidia can fix this with a future driver release. That is when you run 2 monitors the video card never goes into "2D" mode... even when you are not gaming or playing a video. This is why I am forced to disable my 2nd monitor whenever I don't have a need for it.
  • JarredWalton - Saturday, November 15, 2008 - link

    ATI has been doing the same thing for about as long as NVIDIA. There was an issue with 4870 initially where the power saving modes didn't engage properly, but that has been fixed for a while now. NVIDIA is more aggressive, however, on dropping clocks and reducing voltages as well I think.

    Speaking of multi-monitor support, wasn't there a problem with NVIDIA cards and dual monitors with certain 3D engines? Also seem to recall hearing the second display gets shut off in all 3D games on NVIDIA. Maybe that was fixed as well, though.
  • bob4432 - Tuesday, November 18, 2008 - link

    exactly, and if you are not afraid of flashing your video bios, then you can really tweak the power setups for the lower end power "2d" mode to much less than what ati put in as a default. i think ati rushed the 4850 and sounds like 4870 bios when they first came out (extreme heat, lack of real power savings, etc) but hopefully now all that is fixed.

    fwiw - i do consider the amount of $$$ in cooling when getting a real measure on how much it cost to run the pc. i am in phx, az and ac is a must, so in my computer room/office it usually gets about 5-8F warmer than the rest of the condo and therefore that difference needs to be taken into account.
  • BitBodger - Friday, November 14, 2008 - link

    One thing not considered here is the effect of the heat from the computer. That computer sitting beside your desk is also an electric heater constantly warming your home. Live in a cold climate and this is not entirely a bad thing since it takes some of the load from your main heating system. But if you live in a hot climate and depend on air conditioning don't forget that the heater never stops meaning that your AC works that much harder and consumes that much more energy getting rid of the extra heat. And given the inefficiency of AC technology, it costs more watts in the cooling process than are emitted by the heater.
  • Hammarby - Friday, November 14, 2008 - link

    In all these calculations shouldn't you also factor in how much extra it will cost to cool your house when you have a 100-500 watt space heater running for 8 hours/day??
  • Christoph Katzer - Friday, November 14, 2008 - link

    That's why the article calls "The Cost of Running Your PC"........
  • Lifted - Saturday, November 15, 2008 - link

    If "running your PC" increases the demand on your home cooling, then that is a cost directly resulting from running your PC. It is out of the scope of the article since there are too many variables to consider than just the cost of electricity.
  • JarredWalton - Saturday, November 15, 2008 - link

    But if it's cold and running your PC reduces the amount of time you run your heater, then running your PC would cost less in the winter. Besides which, plenty of people don't have AC, so even in the summer there's no added expense. Thus, we chose to limit the discussion specifically to how much your PC costs to run, and how PSU efficiency can play a role in those costs.
  • 7Enigma - Monday, November 17, 2008 - link

    While electricity is 100% efficient (or near enough that we don't need to quibble), it is also true that very few people use it to heat their homes due to $/BTU. Until there comes a time when it is as cheap or cheaper to heat your home electrically I don't think your comment holds true.

    I also agree with the original poster that while not exactly in the scope of the article it is closely related and should have been mentioned. The common position of why spend more money on a more efficient PSU or any other component when the electricity costs show a ROI much greater than the usable life of that product is not accurate when cooling costs are not taken into account. While heating electrically is near 100% efficient, cooling is definitely not.
  • nilepez - Wednesday, November 19, 2008 - link

    Lots of houses are heated with electricity. I've never lived in an Apartment with anything but electric Heat.

    Nevertheless, the heat from a PSU is negligible in the winter (even in the south) and an efficient PSU, by definition, produces less heat, which is especially true when the PC is idle.
  • ZoZo - Friday, November 14, 2008 - link

    Or you can factor in how much less it costs to heat your home when you have a 150W space heater running for 8h/day.
  • Staples - Friday, November 14, 2008 - link

    I have not even read the article yet but I am surprised that was not even mentioned. That often adds 50% more to the cost if you live in a hot climate. Same thing with light bulbs. There is a double savings with CF bulbs.
  • Kyanzes - Friday, November 14, 2008 - link

    I've kind of anticipated a calculator but still a nice read.
  • JarredWalton - Saturday, November 15, 2008 - link

    Isn't that what the spreadsheet is?
  • vandaliser - Friday, November 14, 2008 - link

    All you had to do is buy a Watt Meter which is kind of like a surge protector (but with a digital reader) where you connects your PC's power plug to the meter, then the meter to the main. (just go to ebay search Energy Meter and you will know what I'm on about)

    Take the reading in watts, divide it by 1000 to gives you the number of kwph. Finally, multiply it by the cost of one kwph on your electricity bill and numbers of hours you want to run it for.

    I'm not sure about their expected cost of running, but it actually surprises many people that their PC uses a lot less power then what they expects.
  • Griswold - Friday, November 14, 2008 - link

    Just that truly el-cheapo equipment will give you horribly wrong readings (cos-phi anyone?). Not saying a "watt-meter" must be expensive to give you acurate readings for home use, but there is way too much junk on the shelves out there.
  • Souka - Friday, November 14, 2008 - link

    Buy a Kill-a-watt meter of eBay.... I did years ago, still using it today.

    It'll show real time Amps, Volts, Watt load, KWhr used, and time.
    http://energyseeds.com/2007/10/11/go-solar-and-kil...">http://energyseeds.com/2007/10/11/go-solar-and-kil...

    I just pulled it out for a co-worker to try at her home. :)
  • DeepThought86 - Friday, November 14, 2008 - link

    Given how little power even beefy systems consume, why is it that Anandtech continually reviews rediculously overpowered PSUs? What % of the market is made up of those 600W-1000W monsters? How about comprehensive reviews of the 300-500W market
  • anartik - Tuesday, November 18, 2008 - link

    I would have to say that is a common misconception... There are reasons to buy more power than you "need". I bought "extra" for future upgrades and headroom. The problem with the calculator is most people plug in and come to the conclusion they need some fixed amount of power. All power supplies degrade in output over time with the cheaper ones faster (or use misleading claims as to output in the first place). If the calc says you need 400 and you buy 400 you’re in for trouble as the output deteriorates even quicker from running it at full capacity. The more you strain the PS the hotter its going to run and the louder its fans get. Plus you decide to run out and buy the latest power sucking hardware and voila you need a new power supply.

    I have a 4.3ghz E8500/X48 (SB w/bay,2 sticks DDR2, 2x drives,1 dvd burner and 3x120, 3x140) system and according to the calc I only need 462 with my current OC'd 8800 GTX. My old 550 Antec couldn't hang, screeched harmonics and was replaced with a Corsair HX1000. If I did a worse case upgrade... OC'd Q9550, more HD's, bluray burner and either a single 4870 X2 or possibly two and that power jumps to the range of 650-850 on paper. Factor in overages for peaks, efficiency, deterioration, percent utilization and it ranges from in the ball park to pushing it.
  • nilepez - Wednesday, November 19, 2008 - link

    With all due respect, sites have been pushing large PSUs for years. As I posted earlier, people were trying to convince me I need 600w 3 or 4 years ago, when I built an Athlon 64 Rig with an X800XL: a rig that couldn't not possibly have used 300w, even when overclocked, from the wall, much less from the PSU.

    As for the idea of what you'll need down the road, by the time you need more PSU (esp due age), you could just buy a new quieter, more efficient PSU, with more bells and whistles of equal or higher quality with the money you saved.

    Besides, in 20 years of computing, I've never had a PSU die. The worst thing that happened was a fan died. Bought a new fan and it worked like a champ, and that was some POS PSU that came with my Inwin Case (I think I still use that PSU, 10 years later!).

    buying a quality PSU makes sense. Buying 750w+ PSUs only makes sense for someone running Tri or quad SLI, which means almost nobody. I've seen developers at work return 600W PSUs, because they feared that they'd need more to run to 8800GTs.

    Those 2 cards pull at most 160w...add in a Core2 CPU, and you're looking a rig that is unlikely to pull 300W while playing far cry with Super Pi (just in case there's an idle cycle) running in the background.

    It's almost all marketing hype.
  • Griswold - Friday, November 14, 2008 - link

    I've been saying this since Chris' first (excellent!) review here at AT. I really wish he would push those insane power monsters with extra bling off his workbench and start reviewing those PSUs the majority actually buys.
  • Christoph Katzer - Friday, November 14, 2008 - link

    Next one up will be most probably the Thermaltake TR2 QFan series with 300, 350, 400, and 450W. Everyone cheer up! ;)
  • The0ne - Friday, November 14, 2008 - link

    I would have to agree. If only power requirements were more accurate or rather stated for general usage some of us wouldn't have to go out and buy these 700-1000W PS for a system that draws half of that.

    All in all though, I have to put things in perspective. I waste more time and thus money playing games on my PC; Heroes of M$M 3 and FFXI. So while I can save a little by turning off the PC once in a while and getting more efficient parts, I'll save even more if I just cancel my FFXI account :)
  • Mr Perfect - Friday, November 14, 2008 - link

    Seconded.

    It's especially important to have reviews of reasonably size PSUs when you take a look at efficiency curves on PSUs. PSUs achieve their best efficiency at higher loads, which is why 80+ testing only requires 80% efficiency at 20%, 50% and 100% output to qualify. So a 80+ certified 1000watt PSU will be at least 80% efficient if you're pulling over 200Watts, but if your system draws less then that, efficiency can tumble down into the 70s or 60s without breaking any rules. On the other hand, if you have a 500 watt 80+ PSU, you'd have to draw less then 100watts before you get into the low end of the efficiency curve. For people with HTPCs or budget boxes that really do draw under 100watts, they'll probably want something even smaller, like 300watts.
  • Clauzii - Friday, November 14, 2008 - link

    Agree! Most systems use under 300W total, so a bit more of those would be nice.
  • nilepez - Tuesday, November 18, 2008 - link

    I also agree. I have a Core2 CPU and GTX260, and at idle it's pulling around 120w from the wall. I don't recall what it was pulling at 100% CPU/GPU, but I believe it was roughly 220-240.

    A few years ago, I was talked into buying a 500W PSU, because I needed
    that to power a Athlon 64 and an X800XL.....of course it idled between 70-90w (from the wall) and never hit 200w....ever.

    I did replace it with another 500ish PSU, but in this case, I bought it because the Corsair is very quiet and has modular cables. Power wise, I would have been fine with a smaller psu.

  • mpjesse - Friday, November 14, 2008 - link

    This is a great article. What would be even cooler is if ya'll made some sort of web calculator that could compute the total cost of running your system based on a few known variables (CPU type, GPU type, # of hard drives, time spent idling, etc) and maybe even each U.S. state's electricity rate. That'd probably be a lot of work, but I'd certainly use it everytime I start a new build.
  • Clauzii - Friday, November 14, 2008 - link

    You can try this:

    http://extreme.outervision.com/psucalculatorlite.j...">http://extreme.outervision.com/psucalculatorlite.j...
  • TennesseeTony - Friday, November 14, 2008 - link

    From what I've seen and read, my ancient power supply is at best 65% efficient. Judging by the many comments I've read here on this site, many many others are still using their ancient P4 3.06Ghz systems on a daily, often 24/7 situation, as well.

    I for one don't consider the efficiency rating to be marketing hype, and am very glad to see these better designs.

    Fortunately for me, I held off on the Conroe, saved my pennies, and next week (hopefully) I get to place the order for the final component in my new build...a Nehalem Core i7 920. (Got the Asus p6t ordered from zip....fly last night.)

    Just a few more days and I get to fire up my new 85plus power supply...Woohoo! At idle, with the increased efficiency, perhaps my power costs will remain the same? I could pinch those pennies really tight and reus my old PS, but the new one will pay for itself in short order in my situation.
  • joseps75 - Sunday, November 1, 2009 - link

    My PSU for my 5 computers varies from 3 to 5 yrs old. Mostly I keepupgrading my MB AND CPU'S. Now all my 5 boxes are running quad cores processors. Since I runn them 16hrs daily, I hook up a KILL A WATT EZ to each box to check how much power each box consume. Here are my data for each box tagged by MB NAME: 1) #1 P5K-E $0.0164/HR, 2) #2 P5K-E, $0.0144/hr, 3) P5K-V, $0.0125/hr, 4) #4 P5Q-SE, $0.0156 and 5) #5 M3N78-VM, $0.0105.
    I use my computer hobby to run volunteer research on medical cure for human diseases at Rosetta@home and World Community Grid. They are worthy non profit research to find cure for human diseases HIV, AIDS, ALSHEIMER, CANCER ETC.
    joseps75:-)
  • whatthehey - Friday, November 14, 2008 - link

    I don't think anyone is suggesting that a six year old power supply shouldn't be retired. I looked at the spreadsheet they gave on the last page - damn sweet, I must say! Anyway, I was poking around with some numbers to see what it says about lesser PSUs. If you have a 60-65% efficient PSU with your old system and the PC drew 125W to 250W (for the components, not at the wall), and you run it 8 hours per day with half the time at full load and half at idle, you can get a result for your savings per year.

    Assuming the spreadsheet is correct and I put things in the proper spot, you're looking at a yearly power savings of around $15 to $30 using the above scenario. If you run all the time, your savings would be anywhere from $40 to $100 per year. That's all going with equal power requirements and 60% idle/65% load efficiency to 84% idle/85% load efficiency. The new power supply might pay for itself in a year or two, but for power requirements your PC would take much longer to pay off. But then, more performance is its own reward, right?

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