With the new notebook and the mobile Intel i7-7700HQ CPU the CPU/ASIO load shown in Live 10 (my main host) does not always reflect the actual CPU use also as the CPU does not use it's full possible speed if not needed. Anyway in Live 10 i was able to use 10 instances of the ARP Odyssey plugin with 100 voices overall (each instance with 10 voices Unison) without audio dropouts.
That seems really good! Which preset you did your test? Was your power options set to 'High Performance'? Also what buffer/sample rate did you use?
I will test now in Live 9, Cubase 9 and Reaper 5 with buffer/sample 256/44.1khz. Let me find a 10 unison preset with 10 polyphony.
Ok, I did my tests with Ryzen 5 1600x and iTwo Asio 256/44.1 setup with Live 9, Cubase 9, Reaper 5.77, Reason 10 and FL Studio 12. I was surprised for some results!
The test preset of ARP Odyssey is '030: Feeling Bass' with just one note. Now into the results:
Live 9: 12 instances playing great but with the 13th crackle like crazy!
Reaper 5.77: 2 instances only!! with the 3rd crackle and CPU is going out of the roof! Shocking but very disappointing!
Cubase 9: 12 instances playing great with the 13th crackles (just like Live 9)
Reason 10: 7 instances play very well and clean, but with the 8th I begin to hear some crackles.
FL Studio 12: 12 instances play very well and clean, but with the 13th crackles like Cubase and Live.
I suspect that the maximum of 12 instances in this case because of the Ryzen 5 1600x 6 cores and 12 threads.
Anyway, I must say I'm happy with this result as a CPU but not so about Reaper and ARP Odyssey itself regarding the CPU management and optimising.