So, I got Ableton and set up my rig about 6 months ago but until now have mostly just been doing a lot of reading and playing around with the instruments and effects. I've started working on an 8 bar loop in the session view and am up to about 6 drum parts, a bass line, and a synth lead with cpu constantly up at 70-80% and constant audio glitches and drop outs. The instruments are all a mix of Operators, Samplers, and Simplers with various reverbs, compressors, and mix of other effects as inserts to shape sounds. I've got my Ableton library and various sample folders on an external Lacie USB hard drive. My laptop is an old 1st (2nd?) gen Macbook Pro w/ 4G RAM and a 2.4Ghz Core 2 Duo processor. The interface & main midi controller is an old M-Audio Ozonic hooked up via firewire with the latest Core Audio drivers M-Audio had for it as of a few months ago. I've also got an MPD24 but I've disabled it while trying to debug these audio issues.
In the audio preferences using just the test tone bit I can get the buffer size down to ~256 with minimal cpu usage and no audio drop outs at 96Khz sample rate. However, with the above described loop I have to drop the sample rate down to 44Khz and the maximum buffer size to have it be even slightly listenable at 70-80% cpu and random audio drop outs & glitches.
I feel like the laptop's specs should be fine for this. If I start disabling audio effects the drop outs eventually stop but then I'm left with a fairly minimal amount of those on a small number of tracks so I don't think that should be the proper solution. Should I be looking at replacing the interface? Is there anything else I can try first?