Powering 5 x 480s and a 290 with 1200w PSU

Sequoia93Sequoia93 Member Posts: 130
I have a 1200w gold PSU and want others opinions on whether or not it can power 5 480s and a r9 290. The 290 will be undervolted a fair bit...but I'd still like to dual-mine. I feel like it'll be cutting it close. I ordered the PSU with just 5 480s in mind, but have a 290 that could be doing more than collecting dust.


  • JosevoraJosevora Lisbon, PortugalMember Posts: 93
    Hello @Sequoia93 ,
    let's do the Math:
    5x 480s = 5x 130W (if you undervolt them right!) = 650W
    1x 290 = 300W (well... at normal config...) = 300W
    Other Parts = 200W (+/-) = 200W

    so... you would need about 1150W to run them all...
    Could you do it? YES!!!
    Should you? ... NO!...
    I Think you should give at least a 20% margin for the Cards to Peak (spike)
    But if you trust your PSU (don't do that!) you could technically get away with it...

    By the way... i'm running a stress test on a 1050W PSU whit 7 RX 480s... lol just to see what will blow first! ^^ (i'm serious) the total power draw from the system is ~1040W...
  • Dr_House86Dr_House86 Member Posts: 566 ✭✭✭
    edited September 2016
    It goes easy, and the 1200w psu can give 1200w output and the system dont need 200w.
    But buy a kill a Watt and measure it, to be safe.
  • Masked_ImmortalMasked_Immortal Member Posts: 11
    I have a similar rig 5 rx 480 8g and 1 r9 280x in eth mod only and with 30.5 lowpowerrom it draws out 1150 from wall (little undervolt for 280x) , you stay on boundary but dont go for dual
  • Sequoia93Sequoia93 Member Posts: 130
    I may just end up switching some PSUs around on other rigs... but my system power is well below 200w. The processor pulls under 50w...that plus RAM, mobo, and hdd is 100w max. I guess I'll just find out when my last couple 480s arrive on Monday!
  • JosevoraJosevora Lisbon, PortugalMember Posts: 93
    well... did they arrive?... have anything blown up yet? lol
  • oslakoslak Member Posts: 191
    It will fit. Your problem will be the power draw from the molex.
  • JosevoraJosevora Lisbon, PortugalMember Posts: 93
    edited September 2016
    what you mean exactly @oslak ?
    like too much power for one molex?
    like GPUs + Molex are to much for the PSU to handle?...
    like 4 Molex in one cable?...

    one molex can handle 132W... (the RX 480s !WAS! known to draw more than 75W from the PCI-e slot, but it was reduced with bios fix 16.7.1) so no close to a problem there....

    if you take the 6 GPU, and assuming they are taking 70W from the Molex (overstatement, but lets say), then you have no problem at all since you are SUBTRACTING those 420W (70x6) from the Cards @ the PSU, with the rest going trough the 6PIN and/or 8PIN....

    source on Molex Max Ws see here:

    and use this to convert Volts+Amperes to Watts:
  • Zorg33Zorg33 Member Posts: 220 ✭✭
    Have been discussed many times...
    The Molex connector itself is ok for 100+ W, but the commonly used 18AWG 12V wire can only handle about 100W, so you can use only one molex connector per line.
    There are clever workarounds for that in other topics on how to have parallel 12V lines for your molexes, so you can use all of them.
  • Sequoia93Sequoia93 Member Posts: 130
    Well one of the 480s I received was defective, so I haven't tried it with all the cards yet. The PSU has 5 separate molex strings, so I've paired the 290 with one of the 480s, hoping that the 290 will not be pulling much through the molex anyways, as it already has an 8-pin and a 6-pin power connector.
  • nhandonhando Member Posts: 82
    The 290 is a power hog when dual mining. It will consume over 300watts easily dual mining. It also requires -tt 90 to keep it's temp low to keep hash rate high. Higher fan speed = more power. You can't just dual mine on the 290 alone without doing so on the 480. The 480 dual mining is around 200 watts x 5 plus 290. You won't be able to support that. If you undervolt them all and use the lowpowerrom for the 480 and do Eth only, you can get away with it. no issues.
  • Sequoia93Sequoia93 Member Posts: 130
    The 290 I run undervolted, and with a power limit of -15% to keep temps cool, so I am definitely not using over 300 watts....I don't have a watt meter but in GPU-Z the 290 shows a 200w draw at stock, and about 140w with my settings (dual-mining). I expect it still draws over 200. The 480s are using a custom ROM and are undervolted as much as I could manage.

    So once I get that last 480 we'll see! But like I said before, I will just switch some PSU's around from another rig if I need to.
  • JosevoraJosevora Lisbon, PortugalMember Posts: 93
    @Sequoia93 you just gave me a fresh ideia for my Mining Tool i'm planing on doing...
    Converting the GPU core Watts in to [email protected] (using historical data and statistics...)

    you can contribute to the discussion here:
  • Sequoia93Sequoia93 Member Posts: 130
    @Josevora I saw your thread earlier, but couldn't think of anything... but that's a great idea! I've always thought there has to be a consistent way to convert the two within a reasonable margin of error. It would be very helpful
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