I've tried this brand new CPU in 2 different motherboards with the same problem - HDMI port tries to sync with monitor at 4K. Everything works fine, DVI port on motherboard is at 1080p. I plugged the HDMI cable in to 4K TV and it works fine at that resolution. I can boot Windows 10 with a 1080p monitor plugged in to DVI and plug another 1080p monitor into HDMI after Windows is up and it syncs at 1920x1080.
Has anyone else noticed this problem?