Macbook Pro 2016, 16Gb RAM, 2.9Ghz CPU, Bizonbox3 w/ nVidia GTX 980 Ti 6Gb VRAM. 3 monitors no problem. Add 4th monitor, and fps drops to unuseable (3-5fps). BUT, it appears from the data, that neither the CPU or laptop memory, nor the eGPU or its VRAM seem to be taxed fully when this occurs. So while I have seen other blog entries strongly suggesting that it's the VRAM that causes this to occur, ... well, check out the data I have included. Note that this data (images below) is what occurred AFTER I added the 4th monitor (instruments display). I have included the GTX 980 Ti memory, processor, and the MacBook Pro 2016 Radeon Pro corresponding data, although I was not using the laptop's monitor with xplane at the time.
Monitor config: Main: LG ultrawide 3440 x 1440 (displayport to displayport). 2 side monitors - 34" LG 1920 x 1080 HDMI (one via displayport to HDMI converter cable (GTX 980 has 3 DP ports, 1 HDMI port); 4th monitor via DP to HDMI converter cable - 1920 x 1080 LG 22".
One more interesting data point - why would my performance suddenly decrease (to similar proportions) when I take 3 monitors (one of which is an ultra-wide 4K (3440 x 1440) with displayport to displayport from the nVidia eGPU card, replace it (experiment) with an HDMI 1080p monitor with only HDMI, and a displayport to HDMI converter cable? Is there something about direct DP to DP going on here? Or possibly the technical capabilities of the more expensive monitor?
