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PSU Calculators - Varied results

I've decided that my next upgrade should be a quality modular power supply.

Current setup:
Gigabyte-ud3r-x58a
i7-930 O/C to 3.8GHz
1x 5400 rpm 2tb HDD
1x 7200 rpm 1tb HDD
1x 7200 rpm 3tb HDD
1x 128 GB SSD
1x HD6870
5x 2GB DDR 1333MHz (was 6x, 1 failed)
Asus Xonar DGX sound card
DVD-RW Drive

I've Tried various PSU calculators and get results ranging from 475W to almost 700W

Any suggestions on wattage? Leaving a bid of overhead for additional HDDs.
16 answers Last reply Best Answer
More about calculators varied results
  1. got similar set up in my second pc

    i7-920 at 4ghz etc

    using a decent quality 500w psu
  2. Best answer
    rb420 said:
    I've decided that my next upgrade should be a quality modular power supply.

    Current setup:
    Gigabyte-ud3r-x58a
    i7-930 O/C to 3.8GHz
    1x 5400 rpm 2tb HDD
    1x 7200 rpm 1tb HDD
    1x 7200 rpm 3tb HDD
    1x 128 GB SSD
    1x HD6870
    5x 2GB DDR 1333MHz (was 6x, 1 failed)
    Asus Xonar DGX sound card
    DVD-RW Drive

    I've Tried various PSU calculators and get results ranging from 475W to almost 700W

    Any suggestions on wattage? Leaving a bid of overhead for additional HDDs.


    Hi - I found the same thing with those calculators. Anyway, I use Realhardtech's PSU
    suggestions (that's their expertise) and mcnumpty is right on, they suggest a quality
    500w unit for a sys with one 6870. So - look for a quality unit in the
    500-650w range.

    Yes, 650w is more than you need, but on Newegg now there is heavy promo
    activity on the 650's & not much on the 550's.

    Quality brands: Seasonic, XFX, Antec, PC Power & Cooling, Rosewill Capstone series,
    most Corsairs, most OCZ, and a few others.
  3. whats your budget and i recommand a 750-850 watt if your ever considering sli or crossfire.
  4. rb420 said:
    I've decided that my next upgrade should be a quality modular power supply.

    Current setup:
    Gigabyte-ud3r-x58a
    i7-930 O/C to 3.8GHz
    1x 5400 rpm 2tb HDD
    1x 7200 rpm 1tb HDD
    1x 7200 rpm 3tb HDD
    1x 128 GB SSD
    1x HD6870
    5x 2GB DDR 1333MHz (was 6x, 1 failed)
    Asus Xonar DGX sound card
    DVD-RW Drive

    I've Tried various PSU calculators and get results ranging from 475W to almost 700W

    Any suggestions on wattage? Leaving a bid of overhead for additional HDDs.


    Hi - 6870 in CF needs a quality 600w unit (with 4 pci-e connectors), does not need
    750-850w.
  5. PSU calculators are accurate assuming you can give them accurate input.
    Unfortunately, some inputs are unknowable.
    Like What capacitor ageing factor, or what will your future upgrades be?
    A simple rule of thumb is really sufficient; don't make it more complicated than it needs to be.
    With a normal complement of peripherals(they don't take much) it is the graphics card that drives your psu needs.
    Here is a handy chart for that:
    http://www.realhardtechx.com/index_archivos/Page362.htm
    It is not wrong to overprovision a bit. A psu will only use the wattage that is demanded of it regardless of it's maximum capability.
    If a psu loafs a bit, it will be quieter since the cooling fan does not need to work as hard.
    And... a psu operates most efficiently in the middle third of it's range.

    Your 6870 needs a 500w psu with 2 6 pin connectors.
    Newer 28nm based graohics cards are more power efficient.
    I might look for a 600w unit which will run a card as good as a 7970 or GTX680.
    Pick only a quality unit.
    Here is one list of quality psu's:
    http://www.eggxpert.com/forums/thread/323050.aspx

    I would not pay much more for a modular psu. In anything but a small factor case, there are always places to store the few unused leads.
    You will never recoup the price premium for a gold/platinum/silver rated psu in electricity costs.
    One fair reason fot more efficient psu's is that they will generally be quieter.
  6. rb420 said:
    I've Tried various PSU calculators and get results ranging from 475W to almost 700W

    Don't put too much trust in PSU calculators.

    A good 500-550W PSU would be fine for that build.

    Anonymous said:
    I would not pay much more for a modular psu. In anything but a small factor case, there are always places to store the few unused leads.
    You will never recoup the price premium for a gold/platinum/silver rated psu in electricity costs.
    One fair reason fot more efficient psu's is that they will generally be quieter.

    They're also likely to be higher quality, though you can't judge quality on the 80+ rating alone.
  7. Personnaly, do not use psu calculators.
    What I do is google a review of the GPU and look for totqal system power.
    For instance Idle power for 6870 is 162 Watts
    Max power runing furmark is just over 300 Watts (Games are normally less)
    This dictates a Min PSU rating of 400->450 Watts.
    Your sound card is not factored in so $450 -> $550 is an excellent choice
    6870 CF = 480 Watts w/min 30 % = 625 Watts MIN so 650 Becomes min and recommend maybe max of 750 Watts

    Above all assumes a Quallity PSU!!!!

    Geofelt, Liked your link to realhardtechx and tier levels.
  8. I do not think I even pushed my I7 920(be it only at 3.5Ghz, 5870,3 7200rmp drives and a 5900 rpm. even had more drives in that system for a while.) system past 400 watts ever(and that was with Prime + Game testing).

    Quality 500-550watt units should work fine. If you can get more from a quality brand for a similar price, go for it, just in case you want more hardware in the future.

    Remember, Quality power supplies dedicate the majority of the power to the 12 volt rail.
  9. assuming corsair link is reasonably accurate

    running prime95 and msi kombustor at the same time

    on a 2600k at 5ghz and a 7970 at 1ghz

    i am drawing 420w

    that includes 3 ssd 3 mechanical hard drives and running my cctv as well and a corsair h80

    and a few other peripherals
  10. My Sys - i5-2500 K mild OC 4.2, 16 gigs Ram, 2 SSDs, 2 HDD, Blue-ray witer & 6870
    Just under 350W runing prime95 or furmark (did not run both together).
  11. mcnumpty23, That is some good clock speed you got. What is your voltage?

    I am in about the same board as RetiredChief for use wise(I think OCCT's PSU test got me over 360, but no day to day activity ever gets close.).

    My media center(i5 750[under volt] + 650ti[wish this had an option to lower the voltage at idle to see if i could save more.] is at the other end games under 150 watts most times :) Idles show 23-31(if I trust APC and 31-39 if the cores are not allowed to enter sleep states[playing music for instance])
  12. nukemaster said:
    mcnumpty23, That is some good clock speed you got. What is your voltage?

    I am in about the same board as RetiredChief for use wise(I think OCCT's PSU test got me over 360, but no day to day activity ever gets close.).

    My media center(i5 750[under volt] + 650ti[wish this had an option to lower the voltage at idle to see if i could save more.] is at the other end games under 150 watts most times :) Idles show 23-31(if I trust APC and 31-39 if the cores are not allowed to enter sleep states[playing music for instance])


    yeah--think i got a good chip

    using 1.4v for 5ghz

    have had it higher than 5ghz but not much point really in going for a few hundred more mhz if it means

    pushing too much voltage through it--point of diminishing returns

    still using the power saving features so it downclocks from 5ghz to 1600mhz on idle

    and according to corsair link its 98w in and 97w out when the pc is idle--99% efficiency

    though cant guarantee how accurate corsair link is
  13. 99% efficiency sounds wrong for sure, but the 98 watts in sounds right in line.

    I mean that would be insane to have a high wattage power supply THAT efficient at ANY point(a little over half is the PEAK for most units.).

    Yeah, your chip(cpu) seems VERY good.
  14. nukemaster said:
    99% efficiency sounds wrong for sure, but the 98 watts in sounds right in line.

    I mean that would be insane to have a high wattage power supply THAT efficient at ANY point(a little over half is the PEAK for most units.).

    Yeah, your chip(cpu) seems VERY good.


    yeah as i say cant guarantee how accurate corsair link is

    but most reviews put this psu at over 90% efficiency on all load levels :)

    when using uk 240v

    and a little lower if using 110v

    typical efficiency results

    http://www.hardwareheaven.com/reviews/1610/pg5/corsair-ax860i-digital-power-supply-review-testing-results.html
  15. Best answer selected by rb420.
  16. cheerios
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