SLI Trouble Please Help

Hello, so about a month ago, I bought a second graphics card and a new motherboard. I now have 2 gtx 660s. One of them is the evga 660 sc sig2 and the other is just the standard with a single blower fan. The new motherboard is gigabyte's GA-990FXA-UD3 rev4. My old motherboard was the asus a97 r2.0. The problem is whenever I attempt to start a game, it might run, but it will usually flash red or black then go to a black screen. Then I am required to do a hard restart to get out of that black screen. I was reading a few things online and a few people where saying it was either a faulty graphics card or a faulty SLI bridge. Any opinions or helpful advice would be appreciated. 

 

Full Specs:

FX 8350

GA-990FXA-UD3

16gb ballistix sport 1600mhz

Corsair HX 850

2 Evga GTX 660

1tb WD Black

1tb WD blue

Corsair h80i

a DVD/CD multi drive

LG Blue ray drive

a card 3.0 card reader

and a butt ton of blue 120mm fans

Windows 7 Home Premium 64bit

Question: Do the gtx 660's both have the same amount of ram or are they different?

is your sli bridge on upside down? I did that once.

One thing you can do is disable your sli and test each card individually to see if one has a problem. If both cards check out then we can help you further, but knowing that both cards are good is the best place to start.

 

EDIT:

Also what are the cards the same memory size?

They are both 2gb

I didnt know there was a right ways up, how can I tell?

  • Tried cleaned driver install? 
  • Have you enabled SLI in the nvidia control panel?
  •  Does each card work ok individually?

Colored screens usually means unstable overclock to me but it could be many things. Reset set everything back to stock. Update drivers. All drivers including system drivers.

so its not the bridge is the wrong way

Each card works perfect individually. SLI is enabled. I have the most recent drivers but will reinstall and give an update

Just tested both individually, they where both perfect

Update: I tested both cards and they both worked perfectly alone, i re-seated my ram and also uninstalled and reinstalled my drivers. It has stopped crashing as quickly but still crashes after a bit of gameplay.

I assume you have removed any oc you have on the cpu as well.

Run memtest86 to check your memory's health.

Could be your psu, if you have another close (a friends etc) test your system with that. Or try both your cards in another system.

memory checked out fine

just tried another sli bridge, still crashes after games have been running for a bit

Perhaps try other power pcie cables and even from other power outputs as well. 

Just tried all the drivers in the rainbow, the modern 335.23 work the best, all the others crash even more quickly.

I will try other pcie power cables

the 335.23 just crash the program or the nvidia drivers, while others just lock up my entire system, requiring a hard restart

 

Do you think that my HX 850 is enough for my system?

850 watts is plenty. I ran 680's in sli with an i7 at 4.8Ghz on a HX 850.

http://www.tomshardware.com/answers/id-2151643/sli-trouble.html