Yup. Same here

H81 btc asrock, connected via USB Riser, 750W cooler master PSU.

This rig had 3x rx480 undervolted to:

800mA@1000mhz core clock with mem clocked at 2000

GPU Had artifacts on half of the screen when conected to monitor via hdmi. And with that card connected winodws eould always celrash during boot. RMAed waiting for replacement card to return.