Posted this in "the other RX 480" thread... Adding it here maybe it will help someone.
My RX 480 is also doing the same thing. This has been happening for the last 3 driver revisions. I am on the January version currently.
In the driver there is a setting to lower the PCIe power draw but that did not change anything that I noticed. (My first try)
The only change I have been able to make that made some difference is setting the GPU settings in the game to sync mode. I remember old video cards having a issue with overheating playing this game when they ran wide open. Between that and setting all the AA to the highest settings I get only about 1 CTD per night of about 2 hours of playing. Before I made these changes it was almost unplayable crashing over and over. (My second try and so far best option)
I also notice if it helps, this issue only happens to me when in 3rd person mode and I am panning the view. The screen goes blurry and then black. Then I am back at the desktop. About 1 in 5 times I have a little splash screen in the lower right of my desktop telling me there was an issue and the radion driver is resetting the settings back to default. (I run with the default settings) Another thing interesting is after I log back in to the game and it puts me back in my battle, when I exit the battle (mode) back to my garage there is a super long wait with a black screen before the garage shows up. I would say this takes easily 10x longer than normal but subsequent battles will be back to normal.
I play other game titles and they do not have this issue.