GPU Powering with Server Power Supply

Benni93Benni93 Member Posts: 50
Hey Guys, i searched a little bit on this Forum about this so i decided to make a new thread.

Im planning about to use a Server Supply for my GPUs.

Server PSU is HP 1200W-DPS-1200FB
Ebay Link

i found a pinout for psu at the forums of bitcointalk
Picture Link

My plan is to take my old defect ATX PSUs solder all the PCIe Power Connectors off and solder them to the Supply. Power all the risers and mainboard from my 750w PSU and all PCIe Connectors on GPUs from the Server PSU

got anyone else experience in this?

If not im going to share my progress with you the next days im receiving them.


  • Benni93Benni93 Member Posts: 50
    Thank you for your reply.

    Server PSUs are nerver supposed to be falling down under 92% efficiency but just with a load at 80%-90%.
    Four Graphics Card from me needed 860w, that was to much to handle for my 2x 750 Noname PC Psus so i decided after many other things i saw to try a Server PSU.

    I got no shipping cost for the PSU, just 30€. 2€ for some resistors and 3€ for solder iron, makes me a total of 35€ for 1200w.

    The Solder Thing is no problem, there is enough space for me to soldier. ill post Pictures if this things finally arrives
  • greenusergreenuser 50.8862°N 4.5537°WMember Posts: 439 ✭✭
    edited June 2016
    @Benni93 If you have big soldering irons you are fine. i used a 300w iron. Those large copper areas of the HP's PCB sink a lot of heat away. I think you would be better to find an edge connector for the HP.

    Dell Poweredge 2970 2950 750w Server Power Supply's however will take 6mm spades for 16AWG or 18AWG wire. There are plenty of online mods to fool them to think they have a mobo connected and to slow the fans as default speed is flat out.
    They are cheap as chips, very efficent and can be made to run quietly IF you can read the data sheets.

    I use them for my bitcoin mines, however i solder 10AWG cables between the 6mm spades with a 500w iron and make speed control PCBs on vero-board for making them quiet (and for cranking up the speed and blowing the sh*t out of them once a month) :)

    Enjoy the pics..... They cost me around £25each including bits and bobs.
    I get my 6pin pci-e power plugs by cutting down 24pin mobo plugs and buying new crimp terminals / or by keeping short tails on them and soldering on bigger cables

  • shutfushutfu Member Posts: 320 ✭✭
    damn you did a really clean job there @greenuser . I need to get me some value pack of all the tiny heatshrink sizes like that.

    Also, what 500w soldering iron do you use?
  • greenusergreenuser 50.8862°N 4.5537°WMember Posts: 439 ✭✭
    edited June 2016
    @shutfu Yes, you can ebay heat shrink for pennies.

    These would be some of the best irons to use for this sort of thing

    As above....
    top iron = 125w
    mid iron = 250w
    bottom iron = 35w

    Leave the iron on for 20min before you start.
    Use plenty of flux first, then get the joint hot real fast, get some solder on and get out quick.
    If you need to go in with the iron again, WAIT and let the joint go COLD then have another go.
    Do not apply heat for longer than 10 - 15s (MAX). If it takes longer than that to swet a joint, you need a bigger iron.

    Joins should be shiney and free from flux once done.
    If they are dull or spikey, you were too long with the heat and burnt off all the flux before it got hot enough.
    Remember to clean of all flux once done. It will turn your joins green if you don't

    Good luck!

    More of my work here on bottom of page 10
  • greenusergreenuser 50.8862°N 4.5537°WMember Posts: 439 ✭✭
    Bless no! when i learnt to solder it was with a big lump of copper on a steel bar and then put into the fire until hot enough to melt solder.
    The irons shown are from the 60s and 70s and were made in UK for TV repair.
    You could earn a living back then fixing TVs.
  • Benni93Benni93 Member Posts: 50
    edited July 2016

    Its finally arrived!
    Got it working with a 1000Ohm Resistor at First Pin and Pin 4.
    Drawing 1025w from the psu, got a lot of heat so needs a extra Fan.
    Positive is, its very small and got a lot of power.

    Yea i know my solder work is shit, but it was my first :D
  • greenusergreenuser 50.8862°N 4.5537°WMember Posts: 439 ✭✭
    I have seen better but hay, you had a go, well done.
    Not easy is it? Just as you heat up the joint to add another wire the last one falls off. You need to make a jig to hold all the wires in place, then heat up the area to let the solder flow around all the wires on the track. Maybe wood or cork with the PCB resting on it and staples holding the wires in place close to the joint.... then blast the heat in.
    Brave man! Top job.
    30 EUR for 1200W @ 12v love it!
  • Benni93Benni93 Member Posts: 50
    Thanks for this great tips greenuser, next psu i will try the cork method.
    And yeah i got a shitty iron, just going up to 450°C, i better get a new one
  • greenusergreenuser 50.8862°N 4.5537°WMember Posts: 439 ✭✭
    edited July 2016
    Hay they all go 450deg C but the more watts, the greater the heat inertia and its inertia that counts. Just like a toffee hammer will drive in a 3 inch nail, but a claw hammer will do it better.
    Treat youself to a 100w iron for less than 10 EUR. I bought mine 27 years ago and is still going strong. It will outlast you. Those old German tools are some of the best ever made.
    Post edited by greenuser on
  • Benni93Benni93 Member Posts: 50
    edited August 2016
    Just a Short Update, second psu is up and running :) the first is running now succesful 24/7 for 29days. Im so glad i found out about this Server psus. 2400w for 60€, i love it.
    @greenuser with a bigger iron that was a dream to solder :p
  • Benni93Benni93 Member Posts: 50
    patrik2 said:
    Compared to my worker there are very expensive
  • patrik2patrik2 Member Posts: 156 ✭✭
    @Benni93 , you can solder wires by yourself for free - that's what I did. I provided this link for informational purposes only.
  • Benni93Benni93 Member Posts: 50
    patrik2 said:

    @Benni93 , you can solder wires by yourself for free - that's what I did. I provided this link for informational purposes only.

    Okay Thank u i miss understood :P
    I solder it already by myself :) i bought some package of 10 broken psus and solder the pcie cables off. That saved me some more money.
  • akellyakelly Member Posts: 4
    edited August 2016
    Tried this with some server supplies I had. I got one of them to boot once or twice, and now neither of the Poweredge 2950 supplies (Z750P-00) show any power lights or have any voltage on the output. Replaced some bulging capacitors and that didn't help.

    The Poweredge 2650 supply (DPS-500CB A) powers on fine, and when I hook it up to the GPU the fans spin, but it doesn't output any video signal or show up in device manager. Tried both a 280X and 290X, neither work with the server supply but both GPUs still work fine with the ATX supply. Voltage under no load is 12.44V, a little high, but the ATX spec goes up to 12.6V, and there's no voltage adjustment inside the supply. Tested every pin on the connector, and they all show the correct voltage. The GPU is not on risers but plugged directly into the motherboard. I'm getting a USB riser in a few days to test if that fixes it.

    I'm at a bit of a loss, anyone have any other ideas?
  • akellyakelly Member Posts: 4
    I mixed and matched cables from the two power supplies, and determined that it's the 2 pin part of the 6+2 connector that I crimped that is the culprit. I can measure 12V between the two pins, but there must be a loose connection somehow between the two contacts.
  • Benni93Benni93 Member Posts: 50
    @akelly sorry did not Ever had such problems. And the fact that u measure 12v between all Pins normally say everything fine. Did the graphics Card before the Server psu test?
  • Zorg33Zorg33 Member Posts: 220 ✭✭
    edited August 2016
    You should definitely NOT see 12V between the 2 extra pins of the 6+2pin gpu power connector!!
    They both must be ground.
    If one of them is on 12V, it can fry your GPU!
    Check out the pcie 8pin pinout schematics.

    ATX psus have a 8 pin atx 12v connector for the CPU power that has 4 12V and 4 GND pins, but that shoul never be plugged in a video card!

    I just reread your post and you say that you crimped the connector, be more cautious next time! You are lucky if the card haven't got damaged.
  • akellyakelly Member Posts: 4
    edited August 2016
    Wow thank you, that definitely explains it. I must have been lucky that the sense circuit was 12V tolerant. I was using this pinout, which doesn't make it very clear, and thought the whole bottom row was 12V.

  • Zorg33Zorg33 Member Posts: 220 ✭✭
  • LogicaluserLogicaluser Member Posts: 214 ✭✭
    @akelly wow yeah, the use of green for Sense B and blue for Sense A is quite misleading.

    From what I've read, with modern hardware the 'sense' is often just treated as additional ground, and as a result the #2 12v pin on the 6 pin PCI-E is treated as 12v, instead of the 'proper' spec behavior where that pin is optional/not connected, and only used for the 8-Pin and 6+2 connectors once sensed.
  • stoniestfoolstoniestfool Member Posts: 29
    Just one question. You have the atx hooked to the motherboard. The server psu to the video cards. The server psu is always on ? You can power on/off and restart the motherboard with no issues?

    I was planning to tie the green ps on from atx to the power supply and tie the ground from atx 24 pin to psu.
    Tested this with the atx not connected to a board but a switch between ps on green and ground on the atx.
    If the atx is not on the switch powers on and off the server psu. However, if I hit the back switch to the atx the server psu just stays off. The atx powers on and off like normal. Just a test supply I use.
    I'll figure it out. Just wanted to get running as quick as possible. So always on server using a resistor and atx used normally ?
    Thanks for you time.
  • daweesdawees Member Posts: 17
    @greenuser i have one question for you... do you have connected normal psu + server psu together ? or nah
  • ghapnayaghapnaya Member Posts: 26
    dawees said:

    @greenuser i have one question for you... do you have connected normal psu + server psu together ? or nah

    good question.
    that is my question too
  • magohatamagohata Member Posts: 8
    You can watch this video from Genesis Mining,

    For what can I see they are using a pico PSU for powering the motherboard and the server PSU for the cards (and powering the pico psu).
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