Radeon 17.12.2 (or most recent as of December 25, 2017)
ACER XG270HU 27in WQHD 2560x1440 144Hz FreeSync
BenQ GW2265 21.5in 1920x1080 60Hz
Intel core i7 3770K-CPU 3.50GHz
So I was running 16.10.1 or something simply because the newer graphics driver updates were crashing my favorite games. I heard that 17.12.2 had stopped the crashes and I wanted to experience ReLive. I attempted to update the drivers and my computer froze about 80% through the installation. I restarted my pc and my comp could no longer detect one of my two Rx 480s, specifically the one in the second PCIe slot. I performed a DDU in safe mode and clean installed 17.12.2 again. After taking the "dead" card out and installing it again (take it out, dust it off with canned air, put it back in) it worked and my second monitor had a display. It worked until I switched my comp off. When I booted it up the card was no longer detectable and I could not open Radeon settings. I then took both cards out, think it was maybe the PCIe slot. I tested both one and two slots with both cards individually and separately, and both cards performed well and worked as they should. I tested the power cables, everything was fine. The display cables (one display port cable for the ACER, and a DVI for the benQ) for both cards worked fine. I attempted to perform the DDU process again with zero success. The issue arises with Crossfire. While I attempt to crossfire the cards only one is detectable both by the bios and DxDiag (and radeon settings if it decides to work) I do not know what else to do please help.
Summary: Crossfire doesn't work, individually the cards do work, radeon settings doesn't start after a reboot, DDU process doesn't work.