1. This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.

Using two atx power supplies?

Discussion in 'Hardware' started by yanglu, 7 Sep 2008.

  1. yanglu

    yanglu Hmm...

    Joined:
    20 Aug 2008
    Posts:
    135
    Likes Received:
    0
    My current power supply keeps turning itself off when I'm running games. I have a crossfire hd 3850 setup on a cheap 650W PSU and I think its overheating under load. I've read about dedicated VGA power supplies which fit into a 5.25" bay, but I was wondering would it be possible to get an old 350W PSU and run one of the GFX cards off that, to reduce the load on the main PSU. Thanks
     
  2. lamboman

    lamboman What's a Dremel?

    Joined:
    25 Jul 2006
    Posts:
    1,509
    Likes Received:
    28
    TBH, I would just go and get a new power supply. The old 350W might not be comfortable with the graphics cards, if it is generic. Plus, one power supply is just a tidier option.
     
  3. modgodtanvir

    modgodtanvir Prepare - for Mortal Bumbat!

    Joined:
    28 May 2007
    Posts:
    1,960
    Likes Received:
    2
    Aah, the old 2 PSU trick... brings back so many memories.

    Before we begin, it is probably more sensible, safer and in the current climate, cheaper to just buy a single PSU. I would really recommend one of these:
    Corsair TX Series - 650
    OCZ Stealth Extreme
    Coolermaster eXtreme Power

    Buy if you're set on a 2 PSU set up, it can work very well, and you'll feel infinitely more 1337 ;). And it most definitely works :D

    In my first ever mod, a good few years back now, I found that my 350W PSU wasn't quite cutting it, and being a bit low on money, I was looking to upgrade. Because 500W+ was rather expensive at the time, I decided I'd buy another 350W - and it did indeed work.

    Remember, you have 2 goals:
    Wiring 2 PSUs together.
    and
    Getting them to switch on at the same time.

    Basically, the wiring looks something like this:
    [​IMG]

    A few links for your reading:
    Some dude had a go. Warning: he cut his thumb.
    Some other dude had a go. No blood in this one.
    This might answer some questions

    And a quick guide:
    What would be even better is if you could find something like this:
    [​IMG]

    Just pay very close attention to the pins, make sure you know what you're doing before you start and remember, check twice, solder once :thumb:

    Best of luck,
    MGT
     
  4. modgodtanvir

    modgodtanvir Prepare - for Mortal Bumbat!

    Joined:
    28 May 2007
    Posts:
    1,960
    Likes Received:
    2
  5. wolfticket

    wolfticket Downwind from the bloodhounds

    Joined:
    19 Apr 2008
    Posts:
    3,483
    Likes Received:
    558
    Sorry to be a little off topic but,
    I think this goes to show just how overrated and generally **** cheapo PSUs can be.
    A real 650W supply should have no trouble running that system.
     
  6. Bbq.of.DooM

    Bbq.of.DooM Custom User Title

    Joined:
    12 Feb 2005
    Posts:
    1,477
    Likes Received:
    1
    I don't suggest the coolermaster eXtremepower and OCZ *xstream series.

    I suggest the Corsair VX, TX, and HX
     
  7. yanglu

    yanglu Hmm...

    Joined:
    20 Aug 2008
    Posts:
    135
    Likes Received:
    0
    Thanks alot for everyone's responses. Especially modgodtanvir! I've never seen such a comprehensive response!!! I think I made a mistake with the cheapo 650W. It doesn't have Active PFC and it has two 12V rails both at 22A. I assumed that would enough but obviously not.

    How good is the Hiper TypeM 630W? Is its a tad cheaper than the 650W Corsairs. On paper it has 4x 12V each at 18A. Does anyone know which is better for crossfire setups? Would I be better off to go with the 650W Corsair which has a single 12V rail at 52A?
     
  8. yanglu

    yanglu Hmm...

    Joined:
    20 Aug 2008
    Posts:
    135
    Likes Received:
    0
    I've managed to nab an old 400W PSU from a friend. I've tried jump starting it by shorting the ps-on pin to ground. But it seems to need a large load before it will start. I plugged in several fans and it still wouldn't work. In the end I had to plug the 4 pin 12V ATX plug into an old motherboard before it finally started up. Do you think it will work when I have a graphics card plugged into it. I'm a little hesitant to plug the GFX card in incase something goes wrong and I end up damaging it!
     
  9. Burnout21

    Burnout21 Mmmm biscuits

    Joined:
    9 Sep 2005
    Posts:
    8,616
    Likes Received:
    197
    i have always managed to test start a PSU with nothing connected to it, i tend to stick a fan on it just to give the tinyest amount of load but i am never worried about the PSU no load situation as it is a quick power test no/off job.

    If i was you, find a window and send that crap PSU on a flying lesson!
     
  10. yanglu

    yanglu Hmm...

    Joined:
    20 Aug 2008
    Posts:
    135
    Likes Received:
    0
    I wish I could. Unfortunately I can't afford a new £60 odd pound decent PSU at the moment so I'm stuck with the crap one for now! Believe me, I'll sort it out as soon as I can!!
     
  11. modgodtanvir

    modgodtanvir Prepare - for Mortal Bumbat!

    Joined:
    28 May 2007
    Posts:
    1,960
    Likes Received:
    2
    No probs dude ;) Topic brings back a lot of memories...

    I would always recommend a name brand PSU. Even my Raidmax stock 500W PSU can handle an overclocked 680i and C2d w/ 8800GT. I would really recommend saving up for a Corsair because they are simply awesome PSUs which should just about handle any set up. I've never been too keen on Hyper, though other brands to check out might be Antec and Coolermaster, and I recently had a good experience with 'Arctic Power' which I can imagine is another cheap, but flashy brand - http://www.ebuyer.com/product/124922
     
  12. Burnout21

    Burnout21 Mmmm biscuits

    Joined:
    9 Sep 2005
    Posts:
    8,616
    Likes Received:
    197
    I can say that Hiper power supplies are quality units, i loved mine, just got too old and new connectors were required for new hardware. Most miffed!

    coolermaster psu i dont trust, there is always this feeling of cheapness with there products, a heatsink should be cheap, but electronic items like a PSU shouldn't have that feeling.
     
  13. modgodtanvir

    modgodtanvir Prepare - for Mortal Bumbat!

    Joined:
    28 May 2007
    Posts:
    1,960
    Likes Received:
    2
    Really? I've only ever used one and it was DOA, so my impressions were not good...

    I thought the CM Realpower was an awesome PSU when I used it (neon connectors have that effect on me :p), though apparently their elites aren't up to scratch...
     
  14. DarkEditioN

    DarkEditioN What's a Dremel?

    Joined:
    18 Sep 2008
    Posts:
    77
    Likes Received:
    1
    Just get some high quality new Corsair or Chieftec PSU and forget about that 2 thing :D I would not complicate really... But it is your choice so... God luck
     
  15. staples

    staples What's a Dremel?

    Joined:
    10 Jun 2008
    Posts:
    63
    Likes Received:
    0
    I have done it too....though I wish I had the advice offered by modgod.
    I asked all sorts of electricians and they thought I had a screw loose.

    I did it with one psu connected to the mobo and one turning on separately for the graphics card...for about 3 days till I thought...I don't like this and bought a Corsair psu (well worth the money, very happy with it)

    Anyway, for sure I will be doing it again, why not!!! I have some spare PSU's so thank you modgod, your knowledge will come in handy.
     
  16. yanglu

    yanglu Hmm...

    Joined:
    20 Aug 2008
    Posts:
    135
    Likes Received:
    0
    I've got it working. I didn't link it to the master PSU atx connector though. I thought it'd be safer to use a relay. So I've got a relay wired up to a molex plug on the master PSU which shorts the PS-ON wire on the slave PSU and turns it on. It works a treat and the system hasn't shut down yet:worried:. I've got the second power supply powering only a single 3850 and its seems to handle it fine... Hopefully it'll be alright!
     
  17. gomezzemog

    gomezzemog What's a Dremel?

    Joined:
    23 Sep 2008
    Posts:
    1
    Likes Received:
    0
    Thermaltake Powe Express 450W VGA PS fits 5.25" bay

    I decided to put the 2 ATI HD4850 PCI-E cards running in crossfire mode on the Thermaltake Toughpower 450W VGA PS fits nicely in an optical drive or any 5.25" bay thats open. So far no issues, I am using a igma Shark 635W on the motherboard.

    Vista 32bit Home Premium w/SP1
    Gigabyte GA-MA790FX-DS5 Crossfire MB
    AMD Phenom QC9850 Quad Core BLACK EDITON, Ea Core @ 2.5Ghz (NOT OC)
    Asetek Liquid cooling CU System 20dba
    3GB PC6400 RAM
    (2)Xs ATI HD4850 512MB DDR3 Graphics cards in Crossfire Mode
    500Gb Hitachi725050LA360 SATA-II HDD 3.0Gb/s 16MB Cache 7200RPM
    500GB Maxtor 1 Touch USB HDD EXTERNAL
    500GB WD 5000AAV USB HDD " "
    250GB WD WD25 00JB-00REAO USB HDD External
    250GB ST325082 4A USB HDD External
    (2)Xs LG20x DVD (+/- R) & (+/- RW) Dual Layer
    Thermaltake Toughpower 450W VGA Dedicated PS (Mounted in front of PC In 5.25" Drive Bay)
    Sigma Shark 635W PS (Powering Board)
    ASUS P7131 TV Tuner w/IR Vista Remote and IR Blaster
    HD 7.1 Surround w/ Logitech X-530 70Watts 5.1 speaker system


    Not trying to be cocky, but just to show I have quite a bit of power requirements in this machine, and in the 2 mths that I have had it, I've had no issues at all regarding Power consumption, Overheating, Playing games, ( Ilove the 5.9 index rating I get in the windows experience rating.
    Later Hope this helps someone.
    gomezzemog:dremel:
     

Share This Page