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After....

the very trusthworthy people in everymac.com, the iMac (late 2012) can drive two TB displays with resolution up to 2560 x 1600


🙂:apple:
 
Six displays maximum maybe?

I may be wrong though.

2 thunderbolt ports to 2 HDMI adapter cables.

4 usb 3.0 ports to 4 HDMI adapters.

You would need 4 of these and 2 of these.
 
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