It hurts me to say, but this setup is not valid, and a major downside in general of many modern GPUs and 1440p 120hz screens.

http://www.asus.com/en/support/FAQ/1009038/

How do I set up Surround Gaming [for 3x ROG SWIFT PG278Q monitors in triple monitor setup]?


Two monitor + SLI and Surround + Tri-SLI currently does NOT work with GSync since all display outputs must be connected to the primary graphics card. However, since there is only one DP output on Nvidia graphics, only one PG278Q monitor is supported per card.

Triple monitor can be enabled with one PG278Q monitor per card, but no multi-GPU performance gains are available.

Note: Should a NVIDIA new driver for Surround be released, this KB will be updated accordingly.

The basic problem is that 1440p @ 120hz does not work over DVI-D, its is outside of the bandwidth limitations, so you need to do it via display port, and many modern cards are limited to a single DP port. If I am not mistaken you could theoretically power 2 120hz 1440p screens over a single DP 1.2 port, but I am not aware that actually any splitters on the market support 120hz displays.

Anyone around with more insides on the subject? I just noticed this when ordering my first 290 and wonder if I would run into similar problems? (Well outside of the problem that the card is not powerful enough to push multiple 1440p screens, let alone at 120hz)

@Gimpi Brad Hawthorne maybe? You are most likely the guy in this forum with the most knowledge on this kind of stuff.
edit: Typo in the heading and no one told me *sob*