iMac RTAS Processor mangement

[gtrplyr1]

Just installed PT8 ! What a difference in appearance alone .... it's going to take me a while to get used to this. I guess I'm in the minority but I really liked the way pro tools used to look ... anyhow in a few months I'll forget what PT7 even looked like.

I was hoping to get some clarification from fellow forum members or Digi regarding processor management. I've mostly used pro tools for guitar sessions at my studio and resource management has not been much of an issue but now I'm starting to do much more writing and producing, that along with all of the great new instrument plug in's available make this a much bigger issue. I understand buffer sizes but the thing that is stumping me are the RTAS processor setting and CPU usage limit.

I'm running a iMac 2.16GHz intel Core 2 Duo with 3 GB of ram. Also running 10.5.6 with all updates installed. Is there a optimum setting for the number of RTAS Processors and CPU limit ? Obviously with a iMac I'm limited on choices ... either 2 RTAS Processors or 1 ... frankly 1 seems to work better but I'd love to know why ??? Also why wouldn't you simply put the CPU limit at 99% ? I've tried digging through the manuals but it's really still a mystery to me. Does the kind of work you are doing determine this ? for instance if I'm just tracking and don't really need any RTAS plugs would that be different then when I'm composing and using virtual instruments ?

When using 1 processor and a few plug in's I'm still not getting very good performance ... I tried the 32 samples buffer size and the session won't even play ... does this sound normal ?

The only plug in I have that did not come on PT8 is EZ Drummer and that's not even in the session.


Sorry if I've asked a question that has been answered already ... I've tried using the search feature but still can get an answer.

Thanks,

PD

[rhendee]

bump for gtrplyr1...this is a good question. --R

[rudyrhythmz]

i got the same problem and i have 16 gigs of ram intel quad core 2.66
sometimes when i open a blank session the cpu meter is on 15
and it s the only program open
i think its a bug

[rpb1966]

I prefer to use 1 processor instead of 2, I'm using BFD2 and if I use 2 processors I get the occasional drop out, however if I use 1 processor, I do not get any at all, but as far as I know Digi are gonna iron out this issue with CS updated in the new year.

So if you are having issues and drop outs with 2, switch to 1, but adjust your buffer to 128 and give that a try.

Russ

[DigiTechSupt]

What your settings are depends a lot on which plug-ins you're using. For the most part, if you're using any 3rd party plug-ins (BFD, Omnisphere, etc.) you should reduce the total number of processors available by 1 (if you have 2, set # of CPU's to 1, if you have 8, set it to 7..).

The reason for this - and for things like this:

sometimes when i open a blank session the cpu meter is on 15
and it s the only program open

is that Pro Tools is based on a real-time engine. Many 3rd party plug-ins still have some non-realtime code in them, usually for GUI/graphics. If this code is trying to be executed on a processor that's dedicated to real-time processes, it can interrupt them, causing errors. By reducing the number of CPU's, you open up a separate processor to handle the non-realtime code and allowing things to run smoothly. You still use both processors, just for different types of processes.

As for the CPU usage being at 15% when idle - this is normal, too, and is needed to keep processors 'active' and ready to deal with real-time code. Pro Tools artificially 'spins up' the processor(s) so that there is no idle time between being sent a command and executing it. We have to do this because most processors are meant to 'sleep' when not being used, but the lag between being sent a command and executing it when they're in sleep/idle is too long and, again, interrupts real-time processes, causing errors.

As those processors start doing actual RTAS processing, it will replace the artificial code that keeps them spun up - you actually use that 15% that it shows during idle once the processor gets busy with doing enough RTAS processes to keep it active.

[rudyrhythmz]

i've tried reducing the amount of cpu's or processors sometimes it works sometimes it don't sometimes it request me to add cpu or processors to the session
sometime it just works fine
i mostly use xpand (which is a great pluggin by the way)