newb needs help setting up crossfire

Discussion in 'Videocards - AMD Radeon' started by the_4ork, Mar 22, 2011.

  1. the_4ork

    the_4ork Master Guru

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    GPU:
    Powercolor HD4850
    i bought a 4850x2 brand new old stock still in the sealed box.

    so this would make my machine:
    Powercolor 4850 1gb
    Sapphire 4850x2 2gb
    Phenom X2 7750 2.7ghz
    4GB kingston hyperx 1066 DDR2
    Asrock AOD790GX/128M

    so here is how the story starts out.

    i buy the card, i install the card. take the original single 4850 out and throw it in the pci-e #2 slot. install 4850x2 in the pci-e #1 slot. hook up all power connectors. plug in the crossfire patch cable, and also flip the card on my motherboard into crossfire mode.

    after plugging in the monitor i plug the psu back into power, flip the switch in the back, wait a few seconds and then power the machine up.

    green lights on the x2 card, which is good. the system posts and i have messed up jacked up colors on my post screen so i shut it down.

    trying to isolate the problem i took the following steps:
    4850x2 by itself - no post at all
    flip the mobo back into non-crossfire mode - no post (visual)
    throw the 4850x1 back in, posts fine.

    put the 4850x1 in pci-e slot #1 and the x2 in slot #2 - posts fine with crossfire switch enabled in motherboard

    so now it is backwards from what i had it originally.

    boot into windows. windows finds the new graphics card and installs it. the system locks up.

    boot into windows again - locks up before it gets to the gui

    im frustrated.

    i thought the more powerful card goes into the #1 pci-e slot and the weak one in #2? odd.

    also why am i having lock-up issues?

    and last im having thoughts about the psu. its a enermax 650w dual rail @ 18 amps ea. on 12v

    not sure if this is enough. my next step (logically) seems to be to upgrade the psu and go from there but i almost think it could be a software issue also.

    *i did upgrade the bios before i installed the new vid card but forgot to uninstall the drivers*
     
  2. Mufflore

    Mufflore Ancient Guru

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    GPU:
    Aorus 3090 Xtreme
    It could well be your PSU isnt powerful enough.
    If you use the PC hard, reduce the PSUs maximum output by approx 10% per year, 5% if you dont push it hard often.

    Which PSU do you have?
     
  3. the_4ork

    the_4ork Master Guru

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    GPU:
    Powercolor HD4850
  4. the_4ork

    the_4ork Master Guru

    Messages:
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    GPU:
    Powercolor HD4850

  5. Mufflore

    Mufflore Ancient Guru

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    GPU:
    Aorus 3090 Xtreme
    It looks like your PSU has split power rails.
    If this is true, each 12V lead has a separate max power rating which is much less than the total 12V.
    According to the specs it is 18A per rail which isnt enough for a 4850x2, it requires 20A.
    With aging, the PSU may be down to 16A or less if it is 2 years old.
     
  6. the_4ork

    the_4ork Master Guru

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    GPU:
    Powercolor HD4850
    ok, im gonna jump a spare psu that i have with a 26amp rail and juice the x2 with it and see if that helps. if its on its own dedicated psu it should be fine otherwise i have other problems
     
  7. Mufflore

    Mufflore Ancient Guru

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    GPU:
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    Good idea.
    Try to keep the power on and off times for both PSUs as close to each other as possible.
    This is to prevent leakage currents flowing from the powered circuits through unpowered circuits in ways it wasnt designed for.
    I've done dual PSUs many times successfully, so it doesnt look like a big risk factor, this is fyi
     
  8. the_4ork

    the_4ork Master Guru

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    GPU:
    Powercolor HD4850
    cool, i was getting ready to put my flame suit on, ive done it before but for hdd's back in the day, two computers next to eachother open, one had more accessable power cables than the other :p

    seems to be working, installing the drivers now after sweeping them out with a single card installed. up dual card now for install
     
  9. Detection

    Detection Banned

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    GPU:
    2 x 6850 - CrossFireX
    Its not the PSU - the PSU would shut off if it was overloaded, and it would stink, I know this from trying to run 2 x 6850s on a 570w Trust PSU before my TX950 arrived.

    This is either a software driver issue or a faulty card
     
  10. the_4ork

    the_4ork Master Guru

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    GPU:
    Powercolor HD4850
    got the software loaded and upon reboot it freezes before booting into gui (win 7 windows picture before boot)

    then all the fans and hard drives go to idle and it just sits there. like it gives up on booting but doesnt shut down.

    this only seems to be when its initializing the drivers.

    before the drivers were installed it boots into windows just fine.

    wtf? im on the latest 11-2, should i try a 10 series driver?
     

  11. Mufflore

    Mufflore Ancient Guru

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    His PSU isnt dieing.
    The rails arent strong enough but the internal supply from the transformer is strong enough to cope with the load if a rail is maxed out.
    There wont be any burnt components in this case .

    It depends which methods of protection a PSU has and the levels they trigger at when determining what a PSU will do in an overload situation.
    As this PSU has separate rails, it 'might' trigger on each rail overloading, but it 'might' trigger only when the maximum current for 12V overall is exceeded.
    The overload situation might not even trigger when the PSU has aged a bit, it might never be able to exceed 18A on each rail now.
     
  12. the_4ork

    the_4ork Master Guru

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    GPU:
    Powercolor HD4850
    yeah that was a no go. i still think its a psu issue, the internal (non jumped) psu is still not supplying enough power the the pci-e slots i think.

    i still lock up when the driver loads, most likely because it is enableing the x2 gpu's to come out of idle or something like that.

    sigh.

    gonna grab my wallet and buy that psu i listed above. 60 amps should do it on a single rail me thinks :p x2 + x1 4850's should use up about 30 amps total.

    btw this psu has been humming along since january 2004
     
  13. the_4ork

    the_4ork Master Guru

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    GPU:
    Powercolor HD4850
    ok got a different psu... another antec since it lasted me so long :)

    specs: 750W +12V1@25A, +12V2@25A, +12V3@25A, +12V4@25A,
    100A total isnt too bad

    also newegg sucked me into a sweet deal as usual. damn them for the savings!

    $100 off if buying this case in combo:
    [​IMG]

    i kinda needed a new case... not really but mine is getting a little cramped, especially the hdd area
     
  14. mmsandi

    mmsandi Master Guru

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    GPU:
    5850
    It's not 100A, total is not the same as four of them combined ..it's a 750w psu so it's probably 60A combined
     

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