Crysis 3 easily stresses these video cards at its highest image quality settings with 4X MSAA. You can see a video of our test run and the exact settings we used below.
The 7990 is a wreck without frame pacing, especially when it when it comes to delivering frames to the display. The jitter pattern is pronounced, with punishing frame times of 60-70 milliseconds on the high side. With pacing turned on, the jitter dissipates both in Fraps and FCAT, leaving the 7990's latency plot looking similar to a single-GPU solution's—only with lower frame times.
Meanwhile, the GTX 690's Fraps results show some stuttering that's smoothed out by the time the frames reach the display. I understand Crysis 3 uses a moving average of the last 250 ms worth of frame times in determining how much to advance its simulation from frame to frame. As a result, that variance in the GTX 680's Fraps results shouldn't have too much of a negative impact.
Frame pacing makes everything better. The 7990 trades blows with the GeForce GTX 690 for the top spot in each of our latency-focused performance metrics.
Once again, here are some videos illustrating the different cards' performance.
The 7990 without frame pacing:
With frame pacing enabled:
Now the GTX 690:
Finally, the Titan: