I can't figure out why I can't just get my template to play cleanly without any drop outs or crackles in thickly orchestrated places. I have a brand new slave: Mac Pro, 3.8 Ghz Quad Core i7, OSX Mavericks 10.9.1, 32 gigs of 1600 Mhz RAM, VEP5, and a 1TB Samsung 840 Evo SSD streaming samples. This connects to my other Mac, a less powerful 2.4 Ghz Quad Core i7 sequencer on 10.9.1 with 16 GB of RAM, that is purely dedicated to Pro Tools 10.3.6 (also tried PT 11.1 which didn't provide better or worse results).
I'm not brand new to these kind of setups so I've tried a few things, but I just can't get everything to work as well as it should given what I've just invested in in terms of specs. My samples are all kontakt libraries, and again, streamed from a very fast SSD. I connect to them through 5 instances of VE Pro 5 (Master, Strings, Brass, Winds, Perc). Most of the time it plays fine, but at dense parts it can crackle and drop out (at 512 buffer size). If I bump it up to 1024 then it plays cleaner, but at that point the latency is just unmanageable in terms of playing things in.
I'm not sure why I can't get 512 to work consistently. Sometimes it's fine, other times it struggles. When I play a sequence and look at the activity monitors for both computers, the CPU on the sequencer hovers at about 4-5% (it's just receiving audio), and the slave/sampler runs at about 25%. So I don't think it's CPU, and with an SSD it's unlikely to be disk speed either. What's the problem here? Is there anything I can do to optimize my setup?
Some additional information: Delay compensation in Pro Tools is ON; I'm connecting to each instance with a VEP RTAS set at 2 buffers (changing that to 4 doesn't seem to make a difference), and the threads of my slave are set to 4 thread per instance (again, changing these settings doesn't seem to make a difference to the CPU in activity monitor). If I can optimize any of these settings to get a better setup, please let me know.