I was able to find the list of microcode in the latest April bios ver. for R7/8/9.  I have not been able to figure out which processors these CPU_ID are for.

R7: 06EB, 06EA, 06E3, 06E9, 06E8

R8-9: 06EA, 06EB, 06EC, 06ED

looks like processors with 06EC and 06ED cpuid are the new ones supported by R8-9 only.