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400w psu enough?

Hi, I just recently built a budget system, and I wanted to upgrade from integrated graphics to a Radeon Hd 6870 or a 6850 but I don't know if my psu is enough.
My specs are:
Amd Phenom 2 x4 840 (95w tdp)
4gb DDR3 1333 Mushkin Silverline RAM
Biostar A880G+ Motherboard
Western Digital Caviar Blue WD5000AAKX 500GB 7200 RPM HDD
My psu is an Antec High Current Gamer Series HCG-400 400W power supply. I do plan on upgrading the psu later on, but for the moment should this be enough?
Thank you :)
12 answers Last reply Best Answer
More about 400w enough
  1. You won't need to, i don't think the 6850 uses that much power. The high current series has a ton of amps also.
  2. I was wondering because the 6870 has a recommended rating of 500w, but on the system builder marathon here, the system with a 6870 in it used a total of less then 300, so a 400w for sure is safe? I don't know much about power supplies :/
  3. The 6850 just barely squeaks in there, but you may want to upgrade if you decide on the 6870. Bumping up to a 550 or 650 would give you plenty of wiggle room.

    eta: This thread lists several psu's in that range if you go the upgrade route http://www.tomshardware.com/forum/322966-28-list-recommended-psus
  4. Thanks :)
    I just need to know if it'll work for about a month without frying or anything. The Antec 400w I have is from an older build, and I wanted to use it for a while until I could get around to buying a 500w. I don't plan on overclocking if it means anything lol.
  5. You can even underclock it if you want to be on the safe side.
  6. 400 is more then enough you could even go for a 6870 no problem

    the reason being that you have a good quality psu

    the 6850 draws round 120 watts max on its own and the 6870 round 160 watts which leaves plenty of over head
  7. bluecellman said:
    I was wondering because the 6870 has a recommended rating of 500w, but on the system builder marathon here, the system with a 6870 in it used a total of less then 300, so a 400w for sure is safe? I don't know much about power supplies :/

    bluecellman said:
    I do plan on upgrading the psu later on, but for the moment should this be enough?



    At the wall aka AC, now convert to DC to get the actual load on the psu
    Using the September build / overclocked
    http://www.tomshardware.com/reviews/phenom-ii-overclock-graphics-card,3032-14.html
    rough math
    317w AC with cpu and gpu under load
    ~84% efficiency at that level
    317 * .84 = 266.28 watts DC running power viruses

    A 400 watt psu like yours can handle a 65% load without a problem, other than needing to use a power adapter for the card , till you upgrade it.
  8. Best answer
    For a system using a single Radeon HD 6870 graphics card AMD specifies a minimum of a 500 Watt or greater power supply. The power supply should also have a combined +12 Volt continuous current rating of 28 Amps or greater and have at least two 6-pin PCI Express supplementary power connectors.

    For a system using a single Radeon HD 6850 graphics card AMD specifies a minimum of a 500 Watt or greater power supply. The power supply should also have a combined +12 Volt continuous current rating of 24 Amps or greater and have at least one 6-pin PCI Express supplementary power connector.

    Your Antec High Current Gamer Series 400W (HCG-400), with its maximum +12 Volt continuous current rating of 30 Amps and one 6-pin PCI Express supplementary power connector, is sufficient for a system running with a single Radeon HD 6850. It is deficient by one 6-pin PCI Express supplementary power connector for use with a single Radeon HD 6870 unless you resort to using a dual 4-pin Molex peripheral connector to 6-pin PCI Express supplementary power connector dongle.
  9. bluecellman said:
    Hi, I just recently built a budget system, and I wanted to upgrade from integrated graphics to a Radeon Hd 6870 or a 6850 but I don't know if my psu is enough.
    My specs are:
    Amd Phenom 2 x4 840 (95w tdp)
    4gb DDR3 1333 Mushkin Silverline RAM
    Biostar A880G+ Motherboard
    Western Digital Caviar Blue WD5000AAKX 500GB 7200 RPM HDD
    My psu is an Antec High Current Gamer Series HCG-400 400W power supply. I do plan on upgrading the psu later on, but for the moment should this be enough?
    Thank you :)

    You'll be fine with a 6850.
    The 6870 requires two PCI-E connectors,your psu only has one,you'd need an adapter.(something i wouldn't do)
  10. Thank you everyone for the help :)
  11. Best answer selected by bluecellman.
  12. This topic has been closed by Mousemonkey
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