Here’s my first test…
Well done Steinberg!
Yeah, but how does it compare to 8.5?
I could NOT do that on Cpro8.5
The 200 tracks, are they audio tracks or VSTi tracks?
VSTi and midi (Nexus 2.7.4 VST2 64 bit with each instance using the 65MB ballad piano patch) ,
That’s good news 
As for Audio 44.1 kHz - 24bit (3 second disk preload) on Cpro 9…
I’ve tried 2560 (two thousand five hundred and sixty) tracks and haven’t even got above 40 % !!
I could probably run another 3 - 5 thousand more (for over 7500 tracks) without dropouts.
Curious…buffer settings?..ASIO GUARD 2 on/off?
on a UR44 and newest Yamaha USB ASIO driver
buffer at 1024 samples (at 512 samples the system is at 52% load)
ASIO Guard ON (Low).
46 ms post ASIO Guard latency, (26 ms PRE).
While we’re on the topic…
I could never get more than 50-60 Instrument Tracks with a Kontakt on each in Cubase 8.5 before the ASIO meter went haywire and project stability went through the basement.
Just loaded 200 empty Kontakt instrument tracks in Cubase 9.0.1 and it’s handling it reasonably well. I sure hope this is a good sign.
Was thinking about going back to using VE Pro to balance processing load, but I may not need to now.
Quad-core i7 3.5GHz, 32GB RAM, macOS 10.12.1
Audio interface buffer: 256
ASIO-Guard on High
Further to the 2560 audio track test
Trying to load 2560 instances of cubase’s native “Compressor” (1 insert per track) with a Q-Link (all tracks) in the Mixer crashes Cubase Pro 9 !
lol.
Try loading compressor one at a time 
Good to know it performs better 
This is hopeful. When the Trial is out I will test and hopefully come to same conclusion!
What appen if you send all the tracks to a group track before the main out?
I would not think that comparisons across different systems are valid. Yes, Cubase can be efficient or lax, but the environment is key.
I have tested the same project in C9 and C8.5 and get the same reading here. Cubase is generally well behaved here.
From everything I’ve seen, I doubt it would make any real difference if there are no plugins on any of these tracks. If there are lots of plugins involved then yes, complex routing definitely impacts ASIO performance.
