I tested using the default settings of radeon pro render for blender with some exception of some settings like the number of samples that i changed to 128 istead of 64 in all tests and samples updates per view in some tests
so lets begin
test 1= cpu+gpu/samples per view update:4 = total time 01m.11s.19ms
![render 2 RPR both.jpg render 2 RPR both.jpg](/t5/image/serverpage/image-id/33323i9CEC75ED17FA68F2/image-size/large?v=v2&px=999)
test 2= cpu+gpu/samples per view update:64 = total time 04m.26s.07ms
![render 3RPR both 64 view.jpg render 3RPR both 64 view.jpg](/t5/image/serverpage/image-id/33324i9DA8AE41BA20D0AE/image-size/large?v=v2&px=999)
test 3= gpu only /samples per view update:4 = total time 00m.18s.58ms
![render 4 RPR gpu 4 view.jpg render 4 RPR gpu 4 view.jpg](/t5/image/serverpage/image-id/33325i35A492249B78D2BE/image-size/large?v=v2&px=999)
test 4= gpu only/samples per view update:64 = total time 00m.16s.09ms
![render 5 RPR gpu 64 view.jpg render 5 RPR gpu 64 view.jpg](/t5/image/serverpage/image-id/33326i8F909DC202A3D3C8/image-size/large?v=v2&px=999)
and pc specs
Os: windows 10 1809 compilation 18362.239
Motherboard: asus asus m5a78l-m br usb3
ram: 8gb Hyperx 1600Mhz
Cpu: amd Fx 6300
Gpu: Asus Radeon Rx 460 dual 2gb
Gpu Driver version: adrenalin 19.7.1
Radeon Pro Render Plugin For blender 2.80 version 2.0.112
Blender 2.80