Purpose of 1000 Watt Power Supplies?

I recently finished an i7 build at work and we wondered what kind of power it was using at full load. At the wall we measured about 2.4 amps at 120v, meaning 288 watts. This was with both prime95 and furmark running their tests. At idle it was running in the <200 watt watt range.

Here are the specs:

i7 920 @ 3.11Ghz
EVGA GTX 260
6 GB DDR3
620 GB Western Digital Caviar HDD
6 120mm fans
SATA DVD Burner
650 watt Corsair Power Supply

Granted you want to stay in the middle of your power supply's rated power but in this case I should be fine with a nice quality 500 watt supply. My question is, what are people doing to make realistic use of a desktop 1000w supply? Most of the time this computer will be using just 1/3 of the supplied power. Are these massive power supplies just for people who want bragging rights or is there some legitimate reason for them? I can't imagine 2 more hard drives and 2 more GTX 260's adding 400+ watts.
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More about purpose 1000 watt power supplies
  1. A game enthusiast might use 4 video cards in Quad SLI mode combined with extreme overclocking.
  2. chjade84 said:
    I recently finished an i7 build at work and we wondered what kind of power it was using at full load. At the wall we measured about 2.4 amps at 120v, meaning 288 watts. This was with both prime95 and furmark running their tests. At idle it was running in the <200 watt watt range.

    That's a pretty light load for Furmark and Prime.
    My machine pulls 3.46a running that combo and 1.68a while typing this.
  3. My mobo is the Asus P6T.

    3.1 GHz was the highest I could get it on stock voltages. Since it's a work computer I didn't want to bump those up. I actually built 8 total and they could only get between 2.9 and 3.1 GHz on stock.
  4. I ran into this recently as well. I too have an Asus P6T Deluxe with a 920 OC'd to 3.4Ghz. I was supplied that with 6 hard drives, 12GB of RAM, and my old trusty 8800GTX I'm pulling about 270 watts that occasionally peaks up to 300 watts. ...this is measured by my Zalman fan controller that has a power-usage monitor. When I moved the Zalman unit to my old Q9450 w/8GB of RAM 6 hard drive and my old 8600GT power usage was only at 171 watts.

    So, I guess you really do need to have quad SLI to need one of these gigawatt power supplies. I'm not even using half of the 750 watt Thermaltakes I have. Maybe I will be when I get a GTX285.
  5. I decided to go for a 1050W Enermax Revolution 85+ purely because I wished to OC my core i7 920 and add more GPU's at a later date. Also it was like only £10 more than the 950W version! My build is as follows:

    - Thermaltake Spedo Advanced Package Case powering 7 fans in all 3 of which are LED.
    - Core i7 920 2.66ghz stock speed (will overclock in a few months)
    - Thermalright Ultra-120 eXtreme 1366 RT CPU Fan & Heatsink using artic silver 5 paste.
    - Gigabyte EX58-UD5 motherboard
    - 6 GB Corsair Dominator 1600mhz CAS8 DDR3 RAM
    - Gigabyte ATI HD4870X2 2GB DDR5 graphics card
    - PCie Creative X-Fi Titanium Fatal1ty Champion Pro 7.1 Soundcard
    - 1TB Samsung F1 32mb 7200rpm SATA2 (Will add more drives and RAID when I need more storage space)
    - Pioneer DVDRW
    - Enermax Revolution 85+ 1050W PSU

    So far the fan on this PSU hasn't even come on yet after over 2-weeks of use and it never even gets warm to the touch, even after several hours of Crysis or being left on all day.

    I am so overkill on this PSU for the present system I am powering off it at the moment as I bet from my wall I am only drawing like 250W-280W if that.

    However, the reason I went for a higher wattage PSU was mainly future proofing and the features available. When I add more drives, OC the CPU and add in 1 or 2 more HD4780X2's I ain't gotta worry about my PSU wattage for many years to come.

    Also as and when new GPU models come out, as long as my motherboard supports them, again I don't have to worry about having to change PSU as this one supports 6, 8 and the new 12 pin GPU power leads and furthermore various up and coming CPU features.

    It is correct to say though that 1000-1500W PSU's are really overkill at present for the majority of desktop users including myself. Most people will rarely ever need more than a 750W PSU and can easily get by on 500W. Just always buy a top make and not shoddy cheap ones otherwise you are asking for trouble!

    Think of a PSU as the oil you put in your car; buy cheap poorly refined unbranded crap oil and your engine internal parts will wear out much sooner. Buy a good named and/or top quality oil and your engine will run smooth and engine wear n tear will be prolonged. That is the best way to think of your PSU as better quality ones give more stable voltages, put out less heat etc. It powers everything in your system so make sure you don't skimp when buying one.

    Another problem I find with the present PSU market is if you want sometimes the most feature rich PSU, be it in terms of say controlling software like the Gigabyte Odin, or say the most efficient like the Enermax Revolution then often manufacturers are only starting to ship these PSU's in high wattage form factors, e.g. 850W and upwards, therefore 'forcing' people to have to buy higher wattages that they really don't need.

    It all seems a clever marketing ploy from the PSU manufacturers!
  6. God, the answer is simple. It is not the wattage that you should be worried about, because the wattage means basically nothing. What matters is the amperage, the higher the amperage to wattage ratio is the more reliable the PSU will be, not to mention the higher end capacitors some PSUs have.
  7. That's surprisingly low power. My rig draws 550W or so full load (4870x2 + i7 965@4GHz). That's actually 675 from the wall - 550 is the load the components are pulling from the PSU after compensating for the PSU efficiency. I have a Corsair HX1000W because I might add another 4870x2 at some point, bringing the total into the 700+ watt range. It is true though that for most people, 1kW PSUs are immense overkill.
  8. Well I guess I answered my own question. I got on the eXtreme Power Supply Calculator @ http://extreme.outervision.com/PSUEngine and tried to see what I would need to warrant 1000w.

    i7 965 OC'd to 4.5 GHz @1.6v (<- that even possible?)
    6 sticks of DDR3 RAM
    2 GTX295's
    4 SATA HDD
    1 DVD
    1 Blu-Ray
    1 DVD Burner
    1 Tape Drive (what the hell why not, right?)
    2 additional PCI-e cards
    1 Fan Controller, 1 Front Bay LCD and 1 Front Bay Card Reader
    6 120mm LED Fans
    2 250mm LED Fans
    Koolance RP-1000 water cooling system (I just picked one, this is prob crap? - I don't care)

    Whole system running at 90% load including all drives, fans, etc.

    Gets me 999 watts recommended power supply wattage. I'd imagine that's pulling 650-700 watts tops, depends what overhead they recommend.

    So there I go, if you have the money and desire for that much stuff that's how you can use up all 1000 watts. :bounce:
  9. Heh, my system is supposed to require 1217w if it is all at 100% load.

    i7 920 @ 4.2 v1.55
    6 sticks of DRR3 RAM
    2 4870 X2s @ 800/3600 (that is what I have them at)
    3 SATA HDDs
    1 DVD combo drive
    1 Blu-ray drive
    1 PCIe card (sound card)
    a High end motherboard (MSI Eclipse)
    6 USB devices (mouse, keyboard, reader, MPP3 dock, and any extras)
    7 high performance 120mm fans
    2 high performance 92mm fans
    Swiftech MCP655

    However my PSU never uses more than 700-750w., so I guess it is a bit off. Again the amperage is more important than the wattage.
  10. They do have a healthy overhead built in - my system as currently configured is claimed to use 804 watts with that calculator, but I've measured it around 550. That's with a random access HD test going on, 3dmark Vantage, Prime95, and folding@home simultaneously.
  11. cjl, I have been meaning to ask you. Can you hit 4.2 Ghz on an i7 CPU at anything below v1.5? I know the 965 should overclock better and be stable at lower voltages, but to get above 4.0 Ghz I had to do some major voltage hiking. My CPU stays under 65c load, so it is ok.
  12. Yes - if I overclock with the multiplier alone, with the stock 133 bclk, I can hit 4.13 (31x mult) at 1.38V, and 4.26 (32x mult) at 1.40V. At 1.5V, I can get all the way up to 4.65 (35x mult), although I can't guarantee the full stability of that 4.65GHz overclock, as it hit over 90C in Prime before I decided to stop the test. Besides, 4GHz runs anything I throw at it as fast as I need it to.

    What cooler are you running, out of curiosity? Mine runs in the mid 70s at 4GHz/1.35V for a full prime95 8 thread load, so if you get 65C for a significantly higher voltage and a slightly higher clock, I'd be curious to know how.
  13. Heh I have a GTX 480 and a GTX 240 loop that cools the CPU and my 4870 x2s, which each also have have fans plastered onto the waterblocks making them stay under 70c even when overclocked as far as CCC will go. v1.6 will take me all the way to 4.5 Ghz prime95/superpi stable, but I do not feel safe going over v1.55 which can take me to just under 4.4 Ghz before kicking out. My 920 never goes over 75c even at v1.6.

    If the extreme edition was only $200-$300 more than the 920, then it would be worth it for the unlocked multiplier, but it isn't so I will stick with v1.55. I must say, your OC is impressive!
  14. That explains everything. I am running a dual fan TRUE setup, so about as good as I can get with air. I would stick it on a water loop, but I move the computer around somewhat frequently (being a college student), and having water in it would add that much more weight, and make it that much more of a pain. Besides, for now, I'm quite happy with it as it is currently set up.
  15. Yeah my GTX 480 and all that fluid really weigh down my already heavy TJ07 pretty bad, but hey I love it!
  16. For one overhead with an extreme computer. There is a reason that a tri SLI GTX280 power recommendation is extreme... BECAUSE IT MIGHT ACTUALLY USE IT ONE DAY!!! But seriously... a large power supply has its place in life. I currently have a 1600w PSU for a tri SLI GTX285 build with a Core i7 920, 6gb triple channel RAM, 4 western digital 2TB HDD's in RAID 0 and 2 water cooling units (one for video cards and the other for everything else.)
  17. There are 4 factors you should keep in mind when getting a PSU.
    (1) ALway (as already point out) get a Quality PSU
    (2) Max power Rating should not exceed 5 times idle power. The 20% rule.
    This is a regulation issue. Switching PSUs have a harder time
    regulating the output voltage at the low end. If you can find the spec,
    there is a lower limit that is specified. A quality PSU may even have a
    built in load resitor to prevent dropping below this value.
    (3) max power consumption should fall in the 50 to 80% range of the PSU. Closer to 50 % if you plan on adding GPU's. 80% is fine if you do not plan on increasing the load.
    (4) Pay attention to +12 V power. This is the Rail that consumes most of your power.

    Raven
    "God, the answer is simple. It is not the wattage that you should be worried about, because the wattage means basically nothing. What matters is the amperage....."

    I've noticed this comment in your previous post. Wattage IS Directly related to Amperage, P=IxE. I dought that any one can say exactly what their Amperage on an individual rail is, or the total Current is through a direct measurement - But can come close by measuring the Power (Wattage) delievered to the PSU and calculate the total current by factoring in PSU eff.
  18. RetiredChief, you see my point exactly! Amperage is what matters because that is the true wattage rating. While there are a lot of factors for why some of the amps wont necessarily convert to wattage, it still is much truer than the rating. Case in point:

    Ultra X3 1000w PSU:
    http://www.tigerdirect.com/applications/SearchTools/item-details.asp?EdpNo=4267989&CatId=2535

    Corsair 850TX 850w:
    http://www.newegg.com/Product/Product.aspx?Item=N82E16817139009

    They both have a single rail v12 rated at 70A, meaning a system that wont run on the 850w PSU wont run on the 1000w Ultra either. I compared single rails, which are usually much more honest, but it is the multiple rails that are a lot worse:

    Tuniq 1000w:
    http://www.newegg.com/Product/Product.aspx?Item=N82E16817611005

    This thing has about 68a available, it sucks!

    Antec Signature 850w:
    http://www.newegg.com/Product/Product.aspx?Item=N82E16817371024

    This thing is a true beast, it has about 74 combined amps which is more than most 1000ws!
  19. I knew there was a reason I was supposed to pay attention to the 12 volt rail. What confuses is all those mutiple 12 volt rails that are actually one large rail divided into virtual rails. Can't just add the amps to get a total.
  20. The_Blood_Raven said:
    Amperage is what matters because that is the true wattage rating. While there are a lot of factors for why some of the amps wont necessarily convert to wattage, it still is much truer than the rating. Case in point:

    Ultra X3 1000w PSU:
    http://www.tigerdirect.com/applications/SearchTools/item-details.asp?EdpNo=4267989&CatId=2535

    Corsair 850TX 850w:
    http://www.newegg.com/Product/Product.aspx?Item=N82E16817139009

    They both have a single rail v12 rated at 70A, meaning a system that wont run on the 850w PSU wont run on the 1000w Ultra either. I compared single rails, which are usually much more honest


    Amperage does matter, but you're missing something.
    The 70 amp 12v rating on the Corsair is dependent upon the the 3.3 and 5v load of the system it's installed in, any load on those rails reduces the 12v output, not true for the Ultra, so in reality a system that won't run on the Corsair due to lack of 12v power could run on the Ultra.
    Judging by the 85 combined watts of 3.3 and 5v power my machine uses*, a 62 amp 12v rating on the Corsair 850 would be more realistic.

    * Based on the PowerTuner software readings of my psu.
  21. Actually the Ultra will suffer from the same thing believe me, it was part of an article outlining the exact phenomenon you are talking about. The Ultra is in fact a 850w PSU with very... liberal wattage outputs. My testing slip for my old PC Power and Cooling 750w was rated at 1020w peak output too.
  22. The 1000W PSUs are really for the gaming enthusiasts, who want to maximize their rig. They will put tri or quad card configurations in their system, and most likely a nice sound card, and not to mention the top-of-the-line CPU and motherboard.
  23. The_Blood_Raven said:
    Actually the Ultra will suffer from the same thing believe me, it was part of an article outlining the exact phenomenon you are talking about. The Ultra is in fact a 850w PSU with very... liberal wattage outputs. My testing slip for my old PC Power and Cooling 750w was rated at 1020w peak output too.

    The Ultra is built on an 800 watt platform , but tests at Hardocp and JG's both show it capable of delivering 68-70 amps on the 12v along with loaded 3.3 and 5 v lines, niether makes any claims about 1000 watts being it's "peak" output.
    http://enthusiast.hardocp.com/article.html?art=MTMxNyw0LCxoZW50aHVzaWFzdA==
    http://www.jonnyguru.com/modules.php?name=NDReviews&op=Story2&reid=41

    Would have been back sooner, but along with the stick of Ballistix that decided to go south on me, the updated SoundBlaster driver I installed this morning caused all kinds of problems.
  24. Ouch bro, those damn tracers can be bitches. Try G.skill Black if you are in the need, I had mine at 958 Mhz 4-4-4-12 Timings at v2.2, ya they were fast.

    Anyway you are right, the Ultra is a decent PSU but has had a lot of user issues, quality control issues and the amperage is quite low, mine produces over 80 amps.
  25. The_Blood_Raven said:
    Ouch bro, those damn tracers can be bitches. Try G.skill Black if you are in the need, I had mine at 958 Mhz 4-4-4-12 Timings at v2.2, ya they were fast.

    Anyway you are right, the Ultra is a decent PSU but has had a lot of user issues, quality control issues and the amperage is quite low, mine produces over 80 amps.


    I always have spares on hand, so another set of Ballistix ( no lites ) went right into place. I am however pretty disappointed by them, this is the 5 stick in the past 3 months that has died ( still haven't gotten around to RMA'ing any of them ) It stinks because they are older 2 sided chips that likely wont be replaced with the same.
    I'll keep the Gskill Black in mind, have used the Blue in several machines with no problems, I don't plan on buying any more Ballistix.

    I've read about the issues with the X3, I wouldn't reccomend it, but the tests do show it as being capable.
  26. Thanks so much to chjade84 for starting this thread and everyone who chimed in. I am currently building a system with almost exactly the specs and devices the OP used and a coolermaster UCP 700W PSU. I had gotten pretty worried when I found out a guy at work just built a smaller system with an 850W Corsair PSU. I was thinking I would need to upgrade the PSU to be safe. Thanks to all this information I know I'm good at the very least until I SLI and OC to a modest 3.3 or so.

    p.s. This is the first system I've tried to build myself and tomshardware has helped me at almost every turn, from tipping me off to i7 on. Thanks and keep up the good info!
  27. The_Blood_Raven said:
    God, the answer is simple. It is not the wattage that you should be worried about, because the wattage means basically nothing. What matters is the amperage, the higher the amperage to wattage ratio is the more reliable the PSU will be, not to mention the higher end capacitors some PSUs have.


    Last I checked E =IR still applies. So um...what are you talking about?
  28. Also, you guys need to take into consideration that start up power draw is much higher than power usage when the system is humming along. You need headroom, or you will blow a cap at startup.
  29. pirateclem said:
    Last I checked E =IR still applies. So um...what are you talking about?

    I just think Raven worded himself badly...
    Hes not applying it like that...what hes referring to is how different PSUs (even though theyre 1000w..or w/e) supply different output to the 12v rail which is where u need it

    For Example: Say one PSU supplies 960watts to the 12v rail. That then goes to 80A rating

    Then theres another PSU that only supplies 900Watts to the 12v rail. Then thats 75A. They're both 1000watt PSUs but the actual wattage going to the 12v rail is different between the 2. But this difference tends to be more prominent in lower wattage PSU range (like 750-850)
  30. pirateclem said:
    Also, you guys need to take into consideration that start up power draw is much higher than power usage when the system is humming along. You need headroom, or you will blow a cap at startup.

    Get yourself a Killawatt meter, set it for amperage and watch it during startup. My machine pulls 2.15a from the wall at startup, 3.46 " humming along " running Orthos and Furmark.
  31. pirateclem
    I think I already addressed this and Raven responded to it.
    But a minor correction, What you are refering to is inrush current. Caps normally are the cause of high inruch current and normally don't blow because of it. But it can wreak havoc with inline current protection circuits. Duration of the inruch current is also a important factor. This is more a problem with "el cheapo" PSU as opposed to Max rating.
  32. chjade84 said:
    I recently finished an i7 build at work and we wondered what kind of power it was using at full load. At the wall we measured about 2.4 amps at 120v, meaning 288 watts. This was with both prime95 and furmark running their tests. At idle it was running in the <200 watt watt range.

    Here are the specs:

    i7 920 @ 3.11Ghz
    EVGA GTX 260
    6 GB DDR3
    620 GB Western Digital Caviar HDD
    6 120mm fans
    SATA DVD Burner
    650 watt Corsair Power Supply

    Granted you want to stay in the middle of your power supply's rated power but in this case I should be fine with a nice quality 500 watt supply. My question is, what are people doing to make realistic use of a desktop 1000w supply? Most of the time this computer will be using just 1/3 of the supplied power. Are these massive power supplies just for people who want bragging rights or is there some legitimate reason for them? I can't imagine 2 more hard drives and 2 more GTX 260's adding 400+ watts.
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