Hey guys, I was recently given a Seiki SE39UY04-1 LED TV and have it plugged into a Mac Pro (upgraded to 5,1 from 4,1 with 12 cores, originally 8). I'm running Sierra. My graphics card is a GTX 660. The Seiki does not have Display Ports (only HDMI) so what I did was purchase a Display Port 1.2 to HDMI 2.0 Ultra HD 4K Active Adapter and connected a HDMI 2.0 cable to it. Upon booting, the Seiki still says 3840-2160 @ 30Hz. I was hoping just maybe this would do it but it doesn't. Any of you guys have had success in getting this to work? Everything but the mouse lag is quite nice. I'd just like the lagging to be less. Thanks!