I noticed when I go to the options menu, Overwatch is using my onboard graphics card. I've tried making sure I have the right display drivers, changed Overwatch to be using the "High Performance" option, no dice.
Does anyone have any light to shine on the situation please?
I believe you should be able to choose which applications use which gpu under your graphics card switching options (should be somewhere in the amd suite). The system is supposed to smartly choose in order to save power but often chooses poorly. Alternatively you should be able to turn off the smart switching in the bios and just always use your discrete card all the time. This is actually what I ended up doing on my dell precision when I was having the same issue.