Yes, I got it to work on all three and the render even came out flawlessly with no broken tiles.
Sounds like a dream but there are a few problems, regardless there is massive potential I think, let me explain…
My R9-390x is able to do the BMW2 Benchmark in 54 seconds flat with a tile size that covers the entire thing, this is because it has 8GB of GDDR5 on it.
1.When rendering with other devices as well as the 390x, the tile size has to be smaller which in turn bottlenecks my 390x. The tile size for the CPU must be under 128 otherwise it’s just stupid slow, and the GTX 650 would not do well above a tile size of about 128. This meant that while my 390x would get done with all the tiles it could rather quickly, the last two tiles belonging to the i7 and 650 would make the render take quite a bit longer than if I just used the 390x alone.
I could not tell Blender to just use the R9 390x + 650
I could not tell Blender to use just the CPU+one of GPUs.
I thought it would be better to exclude the CPU as it is the slowest tile and needs to be the smallest too, but you can not configure it like this.
Realtime preview rendering does not work well… if at all. You must be able to specify which device the realtime render uses, because when I was using all the devices it did not seem to work/it was really slow.
Add custom tile size options for each device. If I had this option, I would have made the 390x do around 512, the 650 do around 128, and the CPU around 16. This really would have sped up my overall render time. This effectively removes or reduces the bottlenecking problem.
Let me specify which single device the realtime render uses.
Develop more to reduce crashes and bugs. I didn’t have any issues once I set things up right, but others apparently did.
Hope this helps!