Need to determine why GPUs (GTX 680s in SLI) and (Titans in SLI) are underperforming

Bottom line up front:

I believe that despite switching out different powerful GPUs, my computer consistently underperforms or crashes when it shouldn't be having these issues. I'm not sure what's causing the issues.


My current computer is:

i7-3770K CPU @ 3.5 GHz, OC'd to 4.4 GHz (air cooled)
Asrock Z77 extreme 9
16 GB of RAM (Samsung 30nm UDIMM DDR3 1600)
Windows 8 Pro with Media Center
Seagate Barracuda XT 2TB
EVGA GTX 680 FTW+ (x2 in SLI)
Intel 520 series Cherryville SSD

Monitor: HP ZR2440w and Yamakasi Catleap Q270 (use one or the other when gaming, not both)


I've had it for about a year now and had no real problems. But occasionally my performance seems inadequate for the amount of power under the hood. For example, in Far Cry 3, I've tweaked the settings and used every tool available listed in threads on Tom's Hardware, Steam forums, and every NVidia thread about settings and optimization, and I still get more stuttering and choppy performance than others with much cheaper systems. I tried tying the machine to something more objective, so I ran 3dMark on the system:

This is what I got with Firestrike (3d Mark11)

http://www.3dmark.com/fs/708891

This is what I got with Firestrike Extreme (3dMArk11)

http://www.3dmark.com/fs/675554

The scores seem adequate...possibly not optimized or as impressive as they could be, but powerful enough to run games like Far Cry 3, Skyrim, Metro 2033. But I have trouble getting these games to run smoothly. Often with the higher resolutions and with all the "ultra" settings checked, there's stuttering and choppiness.


Out of frustration, I ordered a pair of EVGA Titan Hydro Coppers. If I had spent some time researching the situation, I would have followed the oft suggested, "buy 780s in SLI instead," but it was a knee jerk reaction. I received the first Titan and it was a flop. I knew it wouldn't be as fast as the 680s in SLI because of the little research I had done prior to purchase, but it barely could keep any of the games running without crashing. Here's an example of a 3dMark score with one of the Titan's:

Firestrike (regular, NOT extreme)

http://www.3dmark.com/fs/705558

This is with completely clean drivers, in the correct PCI slot, with more than enough power from the PSU (It's a Corsair 1200w). I spent 4 days trying to get the Titan to work for more than a few minutes and it kept crashing in every game. The graphics would slow to a crawl, then it would hard crash and reset the computer. So the card got RMA'd and I'm getting a new one.

I should have two Titan Hydro Copper Signatures coming in the mail within the next 2-3 weeks, which I plan to install and run in SLI. I expect it'd be advisable to test each card individually, run scores on it, check the temps, then run them in SLI to ensure one is not weak or garbage.

Is there any problem with my hardware or possibly with the configuration that might be leading to these issues, have I just had bad luck, or is Occam's Razor in effect, and it's probably something stupid like not checking the correct option in some video settings box? (I feel I've read thread on 680s in SLI and Titans in SLI, and issues with Far Cry 3 on the internet at this point before asking)


Thanks,