Black screen on inactive clients

[Vindication]

I recently built a 980x Extreme gaming rig that blows my socks off. Now I am a little disappointed as I am having graphics issues.

I have 2 x 480GTX Gigabyte Video Cards. They are not SLI because I was told if I was going to multibox MMORPG's to set each up with it's own display. So each card is feeding a LED monitor.

I ended up getting a 2nd card because I was running multiple copies of an MMORPG and was getting some graphical glitches when I switched between the characters. After the 2nd card was installed these went away and all was fine for about 36 hours.

The problem I'm having right now is that when I game, the clients over on the 2nd display end up black screening between 2 and 5 minutes into playing, they still respond as I can issue keyboard commands and see the actions performed on the character on the 1st display. So I'm really stumped as to what is causing this.

[Oatboat]

Are you running windowed mode?

[Vindication]

Yes all in windowed mode.

[DrChaos]

Power supply big enough? Or the cards are running hot.

[Vindication]

I have a 1200w power supply so plenty there. Also turned my GPU fans to 100% and the Temp on neither card rises above 40c. So can't be heat either.

[Harrypott]

Faulty hardware? Could try swapping the cards around or running with a single card to help diagnose the issue

[Vindication]

How can it be the cards?

If I run a single card it does the same thing. The "inactive" windows will eventually go black.