3 monitor setup - monitor has no signal

[AdamEcc]

I've been running three monitors off a Fury X for quite a while, largely without issue.

Until this morning, I was running three Asus VN247s, but I've just upgraded the central monitor to a Samsung U224E850 to get silly high res and Freesync.

I've plugged everything in, but only the new monitor and one of the old ones are putting out an image; the left hand Asus is showing up as no signal.

I used to get this occasionally with the old setup and I could resolve it by playing with the cables, but that isn't working this time.

All three monitors work during boot - they all show the BIOS setup screen and the "loading Windows" logo, but the one monitor stops displaying once Windows gets to the login screen. The Display Properties control panel shows a third monitor connected but disabled.

As of right now, the connections are

Samsung - Mini DP -> GPU DP
2 * Asus - HDMI -> Startech.Com DP splitter -> GPU DP
Cintiq (usually switched off) -> GPU DP

When I switched the Cintiq on, it was detected and worked fine; any ideas on why my standard monitor doesn't want to work?

 

[AdamEcc]

I'm not entirely sure whether it was sacrificing the chicken or pledging my soul to Loki that did it, but I got the monitor going before I saw your answer. I really have no idea which change did it

I've made note of your answer for the next time, though. Thank you.