CPU maxes out with only a few virtual synths OS X

[soundforgames]

Hello,

I get maybe 4 or 5 tracks worth of soft synths before my CPU meter maxes out in Pro Tools. Right now I'm composing a piece with bassoon, tuba, trombone, and orchestral percussion samples, and I'm already out of CPU before I add anything else. (The piece sounds funny like this - maybe I'll keep it). Here's my setup:

Power Mac dual-processor MDD 1.25 GHz
2 GB RAM, 4x80 GB hard disks
OS X 10.2.8 / Pro Tools 6.1
HD1 / Control 24 / 192 I/O
MachFive / Spectrasonics Atmosphere / Stylus / Trilogy, Plugsound 1 through 6

No matter which of the soft synths I use, I get 4 or 5 channels before the CPU meter peaks. Is this all I can get out of what was a top of the line Mac just six months ago? The manuals for the soft synths indicate 32 channels of Atmosphere should be possible with the right memory allocation (in OS 9), but I only get 3 or 4. I set the polyphony on each one very low (3-4 voices), I use small samples (under 10 MB) as a test, I've set max CPU usage to 99% and to 75%, and I have the playback engine set to 256 samples, which is already showing some latency on my system. Thanks in advance for your assistance - I feel like I've tried everything.

[axiom]

I just tried a quick test on my G5 dual 2.0ghz with 2.5gb of RAM running PT HD3 6.2r2 on OS 10.2.7. Setting the max CPU usage to 95% I can get 18 instances of Atmosphere RTAS using patches that are anywhere from 4 megs to 34 megs and playing from 18 simultaneous midi tracks with semi-dense chords in an 8th note and 16th note pattern.

I didn't spend a lot of time doing this, but your post made me curious. I can't see how 32 channels of Atmosphere would be possible, unless I am missing something.

[soundforgames]

Thanks for running that test. I'd be *thrilled* with 18 channels. I'd be thrilled with half that, playing just 3 note chords.

The atmosphere manual has a table with suggested memory allocations for DAE, under OS 9, to get anywhere from 8 to 32 instances. I can't do this in OS X though. The manual was written in 2002, which was before the G5 was announced. I'm *hoping* that I'm doing something wrong!

As another data point, I use up all my CPU when using *just* MachFive, with 7 of the 16 MIDI channels enabled. Again, with light polyphony selected and a regular "general MIDI" style music arrangement using modest samples. So I can't even achieve what a typical Roland Sound Canvas could do in 1992. I got more than this using an edirol virtual sound canvas two years ago on a slow Pentium III laptop!

Best regards,
Jamie