Heya Radeon folks,
I'm putting this out here to try to help others who may experience this:
I've noted this w/ my XFX BE Radeon R9 290X & Sapphire Radeon R9 Fury X vid cards using HDMI to my monitor (DoubleSight DS-279W 27" IPS monitor) w/ my Asus RIVG X79 mobo using Asus UEFI. R9 290X has a DVI port which showed no issues (was using this connection prior to switching to HDMI).....
The Asus UEFI won't display properly (graphics clipping) & the mouse won't work properly over HDMI w/ my AMD vid cards (HDMI 1.4 ports in both) but both would work flawlessly across HDMI thru Windows. My Nvidia vid card (GTX 780Ti w/ HDMI 2.0 port) showed none of these issues accessing the Asus UEFI using HDMI & also was flawless across HDMI thru Windows.
It appears that the AMD vid card's HDMI 1.4 spec'd ports aren't compatible w/ Asus UEFI's resolution on ASUS mobos. The AMD card's show to work properly w/ Asus UEFI either thru a DVI connection or DisplayPort connection, but not thru AMD's HDMI 1.4 spec ports.
I tested this also using a DP\DVI adapter (the adapter that came w/ my Fury X) & the Asus UEFI worked well..........but I lost the ability to use my monitor's native res (2560 x 1440), would only allow up to 1920 x 1080 res so this ain't good either.
Should have all this sorted out when my new Cable Matters DisplayPort 1.2a 6' M\M cable gets here Wednesday..........
So until AMD comes out w/ a HDMI 2.0-spec'd HDMI port on their vid cards go DisplayPort if at all possible, or DVI or VGA as last resort for your monitor connection...........I suspect that the AMD HDMI 1.4 port will work just fine connecting a HDTV that spec's out at 30Hz....................
FYI..........................