I have just tested it with my new GPU (R9 390) in 4.9.1 and DFAO is 2ms now while HFGI is 16ms.
I have set these values in the ConsoleCommands.ini:
r.DistanceFieldGI=1
r.HeightfieldGlobalIllumination=1
r.VPLMeshGlobalIllumination=0
2ms for DFAO is nice, but 16ms for HFGI seems to be a lot…