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PSU 7970 Crossfire Overclock PSU requirement

Discussion in 'Hardware' started by SteveD91, 1 Aug 2012.

  1. SteveD91

    SteveD91 New Member

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    Hello everyone, first time poster here. Thanks!

    My question is this:
    I want to upgrade to 7970 crossfire from my single 7970 setup, and I want to overclock this setup to get the most out of it. I currently run a stable 1200Mhz overclock on my 7970, and am happy with this, but would love to know if I can hit around 1100 on a crossfire 7970 setup. Heres my PSU:
    Corsair Enthusiast Series TX 850W V2 High Performance '80 Plus Bronze' Power Supply.

    I am aware this PSU can happily handle two 7970's at stock clocks, but how would it cope overclocked in crossfire? This review came to my attention and shocked me- big time:
    http://www.tweaktown.com/reviews/45...o_cards_in_crossfire_overclocked/index16.html.
    Others say that overclocking a crossfire 7970 setup should pose no problem for any decent 850W PSU, but this graph shows otherwise. I also run an i5 2500k @ 4.5Ghz.

    Will my power supply bottleneck my overclocked setup? Thanks for any help!
     
  2. rollo

    rollo Well-Known Member

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    Your looking at a decent 1kw psu for 7970s overclocked pretty huge power drain vs the 680s ( 480 vs 820 watts)

    850 watt psu is borderline at best and not good for long term either way. If you don't overclock you would be fine on that psu though.

    Power consumption goes through the roof when overclocking 7970s
     
  3. maestro0428

    maestro0428 Master Modder

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    Why the second 7970? Are you going to run 3 monitors? Otherwise its just not necessary. Thats an impressive overclock. Even one at that speed should be able to handle most games with 3 monitors. When running Crossfire you run into microstuttering, driver issues and game issues. I have run both Crossfire and SLI and find a lot to be desired. Just my 2 cents.
     
  4. Pookeyhead

    Pookeyhead It's big, and it's clever.

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    It may be depending on his screen resolution. I game at 2560x1600 and a single 670 don't cut it here at max settings on most games. I NEED SLI... maybe he does too (or Xfire in his case)? Maybe he just likes e-peen and does a lot of benchmarking? It's his rig after all :)


    Anyway... to the OP, the 850W PSU will be pretty much approaching it's limit I'd say. A decent one though should be OK... but it will be working very hard, a lot of the time, so noise and heat will become an issue. The 7970 is one hungry card!
     
  5. Elton

    Elton Officially a Whisky Nerd

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    Eh? I doubt it hits 300W per card. So honestly you can do with a 750w. If it's a seasonic, then the X-650 will do, but that's on a different level of greatness.

    750W 80+ Gold should do you just fine. But his TX-850 is entirely fine.
     
  6. Pookeyhead

    Pookeyhead It's big, and it's clever.

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    Hmm.. If his CPU is OCed, and we don't even know what CPU it is yet. Nor do we know what other devices devices he has installed. Then, if he OCs the GPUs, I don't think that PSU will have the easy ride you think it will. It will be fine, as it's a decent PSU but it WILL be working hard.
     
  7. lysaer

    lysaer Suck my unit! Kirk lazarus (2008)

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    I think an 850w psu with all the hardware overclocked as high as you say would be pretty much at its peak.

    Not to say it won't work, it will probably be ok.

    I think you can pick up a Silverstone Strider for around £140 though and they are awesome psus

    Sent from my GT-I9300 using Tapatalk 2
     
  8. Elton

    Elton Officially a Whisky Nerd

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    He said an i5 2500k @ 4.5Ghz. True it will be working hard, but I doubt an SB system with 2 7970s will exceed 650W in terms of power consumption unless it's either heavily over-volted/overclocked or if they're furmarking it.
     
  9. rollo

    rollo Well-Known Member

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    In a general game benchmark on that tweak town review with slower overclocks they hit 829 watts on the wall, his overclocks are higher

    2 stock 7970s don't need an 850watt psu your correct there but he's wanting to overclock them both to 1200mhz that's a good 200 MHz higher than a stock card. Those 7970s guzzle power under them sorta clocks.
     
  10. Elton

    Elton Officially a Whisky Nerd

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    Hmm, I do remember that. Then scratch my previous recommendation. Apparently 7970s have some pretty crazy consumption OC'ed. 850W to be safe it is.
     

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