Hook up 3 monitors to Mac Mini Late 2014

I have the Mac Mini late 2014 and want to hook up 3 monitors in total. It works great with 2 displays (1x Thunderbolt + 1x HDMI). Once I add a third monitor to the second Thunderbolt port, just nothing happens. What can I do to get my third monitor working?

Solution 1:

Apple's specs show that the late-2014 (which is still being sold today, October 2015) Mac Mini can support up to two displays using its HDMI and thunderbolt ports.
I've confirmed this by trying to plug in 3 monitors directly into the ports on the Mac Mini (two via thunderbolt, 1 via HDMI), with the same results as the OP...one of the monitors is not driven.

The following 3-monitor setup worked for me:

• Late 2014 Mac Mini with 8GB RAM (purchased Oct 2015)
• 3 monitors, each with 1920x1200 resolution
• Monitor 1: driven by Mac mini HDMI port (HDMI-to-HDMI cable)
• Monitor 2: driven by Mac Mini thunderbolt port (I used this thunderbolt-to-DVI cable)
• Monitor 3: driven via USB 3.0 adapter (I used this one from CableMatters and have had zero issues with flicker/performance, although I am not trying to play games or watch video on it...I use it for work).

Some notes:

• You can use a different USB adapter (there are several on the market) but make sure that it's Mac compatible. I previously tried one that had "beta" Mac support and it was terrible.
• Thunderbolt-to-HDMI and Thunderbolt-to-DVI cables are really mini-displayport to DVI/HDMI cables....the Thunderbolt ports accept mini-displayport connectors.
• For the two natively driven monitors (#1 and #2 above) you can use any combination of HDMI<->HDMI/DVI or thunderbolt<->HDMI/DVI cables depending on what your monitor accepts.

Solution 2:

This article might contain information on why this doesn't work.

First off, you're talking about a low-end machine which utilizes shared system memory for its graphics. I drive two Thunderbolt displays with my 2012 Mac Mini with 16GB of RAM and an SSD. The Mini uses a static amount of RAM for video, it does not adjust based on how much RAM is in the machine. As an aside, this is a good reason to max out the RAM on a machine with shared video.

You have a machine with shared video RAM totaling 1 GB, and you're trying to drive two 1440p displays and one 1080p display, a total of 5.76 MP of video output. It's worth noting, the iMac 5K is driving less pixels, and it requires a 2 GB dedicated video card.