Is your Windows fully updated via Windows Update?
Try following this basic procedure installing AMD Driver (little bit more detailed but the same as Benman2785):
install AMD driver:
1) Download the correct AMD Full Set of drivers from AMD Support. Make sure your Windows is fully updated via Windows Update. Windows Must be fully updated because the latest AMD Drivers requires all the latest "Optional" and "Recommended" updates to be installed.
2) Use Windows Uninstall to uninstall current AMD driver and software and disconnect the internet from your computer. Then use DDU (Display Driver Uninstaller) Display Driver Uninstaller (DDU) from Wagnardsoft Forum in Safe Mode. This will eliminate all traces of the AMD driver and software from your computer.
Delete C: \ AMD folder from the Root Directory. Reboot
3) Go to Device Manager and click "Display Adapter" and make sure you are on the MS Basic Display Adapter. If not, uninstall the AMD driver using Properties.
4) Try reinstalling the AMD FULL SET OF DRIVERS that you have downloaded manually. Make sure you disable the Internet to prevent Windows from installing a newer version. So configure windows to prevent it from updating drivers via windows update. So it has been mentioned to disable any anti-virus programs before installing AMD Drivers.
5) If the new AMD drivers installs and works correctly, delete again the C: \ AMD folder from the root directory. To save space on the HDD.
6) Enable both the Internet and Anti-Virus program (if applicable).
7) Go back to Device Manager and check your GPU card driver is working and identified correctly.
Did you purchase your RX470 new or used? If used, as Benman2785 suggested, the vBIOS may have been modified by the original owner.