Hey everyone,
So I wanted to chime in here. In building my own template in ProTools I have found out many things and I ran into problems like this as well. First to respond to the OP Julian, since its working some of the time I would guess that this is CPU bound. And since you are running VEPro and PT on the same computer I would guess that your computer can't handle the load at reasonable buffer sizes. Also since you can disconnect/turn off plugins and it works would also indicate that your CPU isn't able to handle the whole template you are trying to use. To add to this you are running all of your samples off of one drive, which yes I can hear you furiously typing, is SSD but remember that the SATA interface on what I assume is a 2012 MacPro 5,1 is 3 Gb/s add to that (depending on the quality of your SSD) delays in the response times of the SSDs and you just add more stress to your CPU which is trying to do this with the "DAW-that-wins-the-award-for-not-playing-nicely-with-others". I do have a question for you though, you said you have a dual CPU Cheesegrater with 2 3.33GHz CPU's... I couldn't find that as a shipping system built by Apple from the 5,1 lineup. Did you put in "aftermarket" CPU's or is this a stock config? Are you sure that is your base clock or is that the turbo clock speed? I would also be slightly concerned about RAM speed, but I haven't really looked into what speed causes bottlenecks. But its low enough that I would look into it. And finally, I would try setting up your template at 48kHz, in fact I would guess this might solve half of your problem since at 96k you have half the time you would at 48k putting twice the strain on your CPU. The higher your sample rate the less time your CPU has to do the same amount of work, the less time your SSD has time to respond, the less time your RAM has to respond. // Oh and in regards to your follow up post. Were these channels virtual instruments? Reverbs? Any correlation to what you disabled? And what if you started using those VI's, plugins again? Did CPU usage increase? Maybe something in Kontakt is loading, and when you turn it off and then on again it isn't loading until its used? Or maybe its something to do with ProTools and Dynamic Plugin Processing? Do you have that enabled? Maybe try disabling it and seeing what happens?
Jan - I saw this same behavior (if not so extreme) when I was troubleshooting VEPro and PT. And I still do see this uneven core usage reported by PT today when everything is working. However when it didn't work it was because PT was unable to handle the Project I was trying to playback. But since you said that it doesn't matter what VEPro buffer you set I would guess that your slave machine is hitting above 80% CPU usage? Or maybe higher? Whenever this happen for me (i.e. I put a synthetic load on my slaves and run an active VEPro project) I hear dropouts of instruments, pop and clicks, or a playback error, combine with high CPU spikes reported by PT. And its always because my slave CPU usage is too high. Also if you are also running a 5,1 MacPro then I would guess in addition to high CPU usage slow 3Gb/s SATA interfaces, and a single SSD for samples as contributing factors to inoperablility. But a few questions for you as well, are you running 5,1 MacPros? What are their specs (especially CPU)? Dumb question, but are you running a gigabit network on all machines (built in NICS on 5,1 MacPros are Gigabit, just want to make sure you aren't running through a 100 Mbps switch or anything like that causing a bottle neck)? The lowest setting for VEPro I would set is project at 48kHz sample rate, VEPro at buffer 2, ProTools at buffer 256. Anything lower I have found to be unstable or unusable. And finally remember that AVID/ProTools doesn't play well with others, so maybe this is a PT glitch, have you tried the standard trouble shooting steps? Trashing Prefs, rebooting? Uninstall and reinstall? I'm having no problems here running 512 MIDI tracks and 250 voices on my system, so it does work... but it can be a pain to get it to work.
Sorry for the long post, hope it was helpful.
-Walter