Connect 3 External Displays to iMac (Retina 5K, 27-inch, 2017) Is it possible to connect 3 external displays (for a total of 4, including the built-in 5K display) to an iMac Retina 5K, 27-inch, 2017? I have the Radeon Pro 580 with 8GB of VRAM.

I do not need the external displays to be high resolution. In fact, all three of them need to connect via VGA using the following resolutions:


External displays 1 &amp; 2: 1920x1080
External display 3: 1280x720


If necessary the 3rd display could be a different connection type (e.g. DVI) and/or resolution. The specs for external displays 1 &amp; 2 are not negotiable.

I've reviewed this iMac's specs which seem to say only 2 external displays are supported via the two ThunderBolt 3 (USB-C) ports. However in my research about ThunderBolt it seems like it should be possible to run two simple displays off of one port.
I have attached 3 external displays to my MacBook circa late 2011. I stumbled across this nifty product:
Diamond USB Multi-Display Adapter

1 monitor is via the MiniDisplay port and 2 are attached to a USB hub (at USB 2.0 speed).

However, on some forum (that I can't even find anymore) someone mentioned this could possibly cause my CPU to overheat. I have used this 3 monitor config for a few days with no problems and I just started monitoring CPU temp.

I suspect that the performance on those USB monitors is awful? I've no idea. I know so little about graphics, I don't even know how to test them for performance...