With driver version 17.3.3, I could overclock my GPU core from 925 MHz to 1050 MHz with no issue, but with 17.4.1 and 17.4.2, it makes my second display go nuts. Here's a video to illustrate the issue: VID_20170412_170626~2.mp4 - YouTube
Here's my specs:
GPU: Sapphire Dual-X Radeon R7 265 2GB
OS: Windows 10 64-bit (Creators Update)
Displays: ASUS VX238H 1920x1080 @ 60Hz (in the digital-only DVI port on the card, HDMI on the display), Dell 2007WFP 1680x1050 @ 60Hz (in the analog DVI port)
Motherboard: ASRock 970 Extreme4
CPU: AMD FX 6300 @ 4.1 GHz OC
PSU: Corsair CX600
RAM: 8GB dual channel (2x4 GB) 1600MHz DDR3
This was happening prior to the Creators Update, so at least that can be ruled out.
I have tried a clean uninstall and reinstall of 17.4.1 and 17.4.2, but the issue persists. Another thing worth noting is that when I first tried upgrading from 17.3.3 to 17.4.1, my Global OverDrive was changed to Global WattMan, but I didn't remember to check if that was also the case when upgrading from 17.3.3 to 17.4.2. After a clean install of 17.4.2 however, it was in fact OverDrive instead of WattMan.