What CPU do you have? You can search 3dmark results and enter your gpu's and CPU and see what other people got. I looked up Titan x 2way sli and i7 4790k and am seeing most people are getting around 15000 or more so you're pretty close. Most of them have overclocked their CPUs and gpu's as well so keep that in mind
Running a 5960x on a x99e-ws 3.1 with a 1600w P2 EVGA Power Supply, Custom Dual pump / Loop liquid cooling system with a 560 rad and a 480 rad. Might just try and look for firmware flashes to get some more out of her.
I found out the issue.. I had to set windows 10 into the resolution of the test.. otherwise it was doing scaling and eating up a bunch of power... I ended up scoring 18200 on my test.