Was having problems running the game at 5760x1080 on my Titans, also noticed one of the cards was doing all the work, to enable SLI you need these beta drivers:
http://www.geforce.com/drivers/results/75798
Game runs much better and has less texture loading issues after installing it, it also helped run the game smoother on my laptop after I downloaded the notebook version.
I ended up buying the digital version from Gameholds.com for $39.33, my CD-key was emailed to me about 15mins after the transaction was approved, but my Doom key is not working, any of you guys had luck with the Doom beta key?
The game is lots of fun, I'm really liking it, just what I needed for the long weekend, and I hope I can finish it before Watch Dogs is released