20 fps / basically unplayable performance?
over the past few patches, dota 2 has become successively borderline unplayable on my mid-2015 macbook pro (2,5 GHz i7, 16 GB RAM, Radeon R9 M370X, running Sierra 10.12.3). fps with graphics on lowest settings possible starts out around 120+ but drops very quickly to around 25 once creeps spawn and down to 10 and worse during graphically intensive teamfights. performance is equally poor in windows 10 bootcamp... but other graphically intensive software works just fine so i'm not inclined to believe that it's my hardware?
You Definitely have Driver problems, Or may be the Integrated graphic of the CPU is interfering with your discrete graphic. I have a 7 years old graphic (Radeon 6850) and get 60fps constant on highest setting 1080p. Dota2 is an extremely hardware friendly game comparing to other games.