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Computer won't start when 3rd display connected

  • Computers
  • Graphics Cards
  • Displays
  • Graphics
Last response: in Graphics Cards
a b U Graphics card
June 1, 2014 4:47:48 AM

Hi all, been posting here for a while but now I need help, I've never seen this one before and a I couldn't turn up any help on a trusty Google search either!

I've been using 3 displays on my PC for about 18 months now, no issues. However, all of a sudden my computer will not start: (I have fans starting, MB lights on, I can hear HDD & DVD have power - BUT NO keyboard/mouse lights and, more importantly, no displays).

After lots of messing about (reset bios, re-seated RAM, checked all internal cabling), I unplugged two displays... voila, computer starts no problem. Boots fine. Once the computer has started, I plugged my two additional monitors in, detected and connected immediately. Temps are fine. I can game across all 3, no issues. BUT, the issue is completely reproducible. Any time I try to start the computer with all 3 displays connected, I get nothing but fans, a brief faint HDD chatter & darkness.

I don't believe the computer is actually booting either as I can tap the power switch and the computers shuts down within a second. It won't do this if windows is booting. So something to do with the third display is actually stopping the computer from booting.

The only thing I changed about a week ago was a new displayport cable, however the problem didn't start straight away and the computer will still boot with that new cable connected as long as one of the displays is removed.

Obviously this isn't a major issue, I can just clamber behind my computer every time I start her up, but that's not hardly dignified. Any suggestions would appreciated.

Specs are:
- HIS 7950 IceQ Turbo (stock)
- 3xDell 2412M (2 connected miniDP to DP, 1 connected DVI)
- PSU Corsair TX-750
- Everything else: Intel i5-750, Gigabyte P55 MB, Samsung 830SSD (128), WD Green 1.5TB

More about : computer start 3rd display connected

a b U Graphics card
June 1, 2014 11:57:30 AM

Try connecting the monitor to different port, i.e shuffle them, or use a different interface to connect to your monitor,like via HDMI or VGA, if possible and if your Graphics card/monitors can support.
a b U Graphics card
June 1, 2014 12:01:55 PM

What he said. I'd try connecting each monitor individually with each connection that you can and see if maybe it's the monitor or maybe the connection type that is causing this issue. It seems odd but with hdmi and dp both pushing audio there could be some sort of conflict going on.
a b U Graphics card
June 2, 2014 3:58:31 PM

Thanks guys. After some further testing, using different connection types, I've just discovered that the issue is actually intermittent too. It worked twice with all 3 connected, and I thought it would consistently work when I unplugged the DVI (leaving 2xDPs connected. This morning however that didn't work and I could only get it to boot with just the DVI and neither of the DPs. Grrr.
Unless anyone has any brilliant suggestions I'll just wait and see. Perhaps if something is failing is might go entirely and then I've at least got a chance of isolating and resolving or replacing it. This intermittent stuff makes it nearly impossible to isolate the problem.

If it is the graphics card I hope it goes soon 'cause I've only got 2 months left on warranty!

Thanks for your help. Any other suggestions welcome!