7850x2 psu help

Hi all, I haven't got a clue when it comes to psu's, I had a look at a few psu calculators online but with very conflicking results. :??:

I have a XFX 550w pro core edition

http://www.amazon.co.uk/XFX-P1-550S-XXB9-PRO550W-Edition-Supply/dp/B004RJ8EKI/ref=sr_1_2?s=computers&ie=UTF8&qid=1360701715&sr=1-2

Will this psu be ok for 2x asus 7850's OC tiwn frozr's?

other specs

P8Z77-m pro
i5 2310
8gb ddr3 (2x4gb)
2 sata harddrives
2x fans
1x dvd-rw

thanks for any help!
15 answers Last reply
More about 7850x2 help
  1. Hi Mattck,
    Now a good quality PSU of lower power is always better that a bad quality PSU of higher powern and you have a PSU of good quality. However, most GPU manufacturers will recommend a PSU of at least 600W. This is most likely to cover their own backs and your CPU doesn't use a lot of power.
    You will probably be okay with a 550W FOR NOW, however it will be under a VERY high load and if you overclock your hardware or use it heavily, it could fry completely. Please note that under max load 1 HD 7850 uses around 250W, so 2....

    Personally if I had enough and was in your situation, I'd go for a 600-700W PSU. Not only will this cover your 2 7850's but it will safeguard you for upgrades in the future :) Heres a decent 650W: http://www.scan.co.uk/products/650w-corsair-enthusiast-series-tx650m-modular-85-eff-80-plus-bronze-sli-crossfire-eps-12v-quiet-fan-

    Regards,
    Dan.
  2. Since the 7850 overclock nicely I would move up another 100w or so but with everything running at stock a good quality 550w will do fine.

    A 7850 is 100-130w under load.
  3. I have a Corsair TX750w that I have been using for 5yrs now and still running strong. You have to make sure the PSU you buy also has all the necessary PCI-E connections.
  4. popatim said:
    Since the 7850 overclock nicely I would move up another 100w or so but with everything running at stock a good quality 550w will do fine.

    A 7850 is 100-130w under load.

    Yeah, sorry for the misleading info, found it on a website... I thought it was a lot though as my old HD 6850 only uses 125W!
  5. The 550 should work. Each 7850 only needs one PCIe cable.

    You will be able to tell if you need a more powerful PSU because your system will reset and reboot under heavy graphics load - gaming, primarily.
  6. That PSU should be adequate so long as you don't do any heavy overclocking or otherwise very power-consumption intensive upgrades beyond the two 7850s, but it would run the PSU at a somewhat high load during gaming. Not dangerously high, but high.
  7. Thanks for the help all! I think I'll stay with this then till i want to overclock them.

    Thanks again!
  8. jsc said:
    The 550 should work. Each 7850 only needs one PCIe cable.

    You will be able to tell if you need a more powerful PSU because your system will reset and reboot under heavy graphics load - gaming, primarily.


    I think he is referring to a non reference Asus 7850 which
    might require two pci-e connectors.
  9. Are you sure that they need two cables? I've known several cards that had a more advanced cable support than was necessary for running them at stock and they usually ran fine with the regular cable combination for their type of card.
  10. blazorthon said:
    Are you sure that they need two cables? I've known several cards that had a more advanced cable support than was necessary for running them at stock and they usually ran fine with the regular cable combination for their type of card.


    No - not sure - the Asus specs say up to 150w - 1additional 6 pin needed.
    I don't know if "additional" means two or one.

    There are non-ref 7850's that require two, but the specs are
    pretty clear. On the 3 Asus models I looked at it isn't clear.
    I suspect they may need only one, but the 150w made me
    think twice.
  11. Well, for 150W, you can get up to 75W from the PCIe slot and up to 75W from a single six-pin cable for a total of up to 150W, so it seems like they are single-cable cards.
  12. blazorthon said:
    Well, for 150W, you can get up to 75W from the PCIe slot and up to 75W from a single six-pin cable for a total of up to 150W, so it seems like they are single-cable cards.


    Most likely correct, if they hadn't used the word "additional",
    I wouldn't have thot twice about it.
  13. Yeah, the cards only a single 6-pin, the system requirements in the msi book says 75w.

    The psu actually has 1 6-pin cable, and 1 6+2-pin cable.... don't if that helps lol, as I said I haven't a clue about psu's.

    the psu box says:

    44A +12v

    24A +3.3v

    24A +5v

    0.5A -12v

    2.5A +5vsb

    =550w

    It also says its true wattage guarantee! (I don't know how true that's is lol)

    So do u think it will be ok if I don't overclock?
  14. I would probably want a quality 650w at minimum for dual graphics like those.
  15. mattck said:
    Yeah, the cards only a single 6-pin, the system requirements in the msi book says 75w.

    The psu actually has 1 6-pin cable, and 1 6+2-pin cable.... don't if that helps lol, as I said I haven't a clue about psu's.

    the psu box says:

    44A +12v

    24A +3.3v

    24A +5v

    0.5A -12v

    2.5A +5vsb

    =550w

    It also says its true wattage guarantee! (I don't know how true that's is lol)

    So do u think it will be ok if I don't overclock?


    Hi - your XFX 550w is very close to the 575w realhardtech suggests, but the
    550 also has 44a on the +12v rail. 528w of the total on the
    +12v rail is very good. You'll be fine, and even do moderate OC
Ask a new question

Read More

Power Supplies Components