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PSU power question

Discussion in 'Graphics Cards' started by Rajii, 8 Oct 2009.

  1. Rajii

    Associate

    Joined: 28 Sep 2005

    Posts: 9

    Last edited: 9 Oct 2009
  2. fornowagain

    Sgarrista

    Joined: 3 Nov 2004

    Posts: 9,833

    Location: UK

    Well that depends on the rest of the system, but in a typical system it would do so with ease.
     
  3. Rajii

    Associate

    Joined: 28 Sep 2005

    Posts: 9

    Nothing major in the pc, couple of sata hd's, one external usb hd, and an asus xonar sound card. I've been getting a lot of "display not responding errors" and pretty much ruled out everything out except for psu and the card itself.
     
  4. fornowagain

    Sgarrista

    Joined: 3 Nov 2004

    Posts: 9,833

    Location: UK

    You have more than enough overall power, but it maybe the individual rails are overloading. Some PSUs actually only have one rail even if they claim more, others have semi-individual rails with over-current protection. One rail loads too much and it trips. Try cross-loading rails, find a molex to pci-e adapter or move the pci-e connectors around, that may pull a different rail into play.
     
    Last edited: 8 Oct 2009
  5. Cd0gz

    Gangster

    Joined: 10 Sep 2009

    Posts: 227

    Location: Lots of different places

  6. Rajii

    Associate

    Joined: 28 Sep 2005

    Posts: 9

    Thanks guys, will have a look and let you know what happens
     
  7. drunkenmaster

    Caporegime

    Joined: 18 Oct 2002

    Posts: 33,190

    A half decent 850W will run 2x295gtx with a 8gb, highly clocked quad core system without issue(700W is pushing it, 750W is very close, 850W and you'd be fine).

    A basic sli/crossfire setup with 2 high end cards is unlikely to ever push more than 500W load, frankly most won't get far beyond 400W even overclocked.

    Check the manual though, almost every PSU will tell you which connectors are on which rails(if multiple) so you can spread the load rather easily. IE you might have 4 pci-e connectors and the manual might say 2 are on the same rail as the mobo or CPU power headers, and 2 are on their own rail, you'd want to use the 2 on their own rail if you could.

    Obviously depends on your PSU, my TT psu is modular and tells you which connectors will be on which rail so is very easy to spread the load out as evenly as possible or making sure main components have the most spare juice possible.
     
  8. james.miller

    Capodecina

    Joined: 17 Aug 2003

    Posts: 19,180

    Location: Woburn Sand Dunes

    its a bit more than that for a 295, they consume around 200w's on there own. in a *balanced* system using two of them id expect 550-600w consumption. Still easily achievable with a decent 850w psu either way :)

    still less than a 4870x2 i might add!
     
  9. Rajii

    Associate

    Joined: 28 Sep 2005

    Posts: 9

    Tried that and didn't help, but I did come across the following which is "supposed" to help, but whether it does or not I'm not sure.

    HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\GraphicsDrivers

    TdrDdiDelay (REG_DWORD) 20
    TdrDelay (REG_DWORD) 20

    TdrLevel: REG_DWORD. The initial level of recovery. The possible values are:�
    TdrLevelOff (0). � Detection disabled.
     
  10. Antx777

    Wise Guy

    Joined: 23 May 2004

    Posts: 1,904

    I have that PSU (OCX 850), and running a pair of GTX8800's, and a 3.8 QX9650 with it. The GTX295 (according to that calculator above) uses about 40 watts **LESS** than TWO GTX8800's - so it will work obviously - don't know about two though....

    Also in the review of the PSU it specs "18a 18a 18a 18a" on 12V rail, whereas on the PSU itself it reads 20a 20a 20a 20a.


    ~Ant