High CPU usage with empty project, OSX only Live 8.1

[zeekay]

I have Windows 7 bootcamped with OX 10.6.2 (had same issue with 10.6.0 as well), on a new macbook pro. I've tried doing completely fresh installs but I can't seem to alleviate the problems I'm having with high cpu usage(?) while doing seemingly nothing. If I open a new project (1 midi track, 1 audio track, no clips, no instruments) on OSX I'm seeing roughly 13% cpu usage with onboard sound, 9% with my focusrite saffire. 44.1khz, 16-bit, stereo output only, no inputs, buffer size of around 256 samples. In windows task manager reports 0% until I actually do something. Just activating the i/o in os x seems to cause pretty large cpu usage increases. Is this normal? In terms of ableton live reported cpu available, OSX projects always report slightly more cpu usage than the same projects/settings in windows.

The real problem though, is that a combination of low latency, high cpu usage leads to terrible audio glitching/underruns on OSX for me. Experimenting with my saffire & onboard sound, it seems setting a low buffer size (sub 256 samples) causes issues with cpu usage over 50%. Just as a simple example, I can set the buffer size to 128 samples in windows and OS X, and on windows I can run the cpu usage simulator at 80% w/out glitching, but not on OSX. Anything under 256 samples (with 44.1khz/48khz audio) begins seeing diminshing returns. I'm able to use my saffire with a buffer size of 60 samples in windows w/out glitching at up to 80% cpu usage on the simulator, large projects are not a problem for me at all, and a lot of them use around 70-80% cpu. Switch over to OSX and there is no way I'm going to be able to work with them without freezing a lot of tracks.

I figured the performance would be roughly in parity across both platforms. Is this sort of high cpu usage (even with empty projects!) normal? Are there any tweaks I can do? I've tried setting all audio to 44.1khz 16-bit, disabled airport/bluetooth, killed dashboard, but I don't know what else I can do to increase performance on OSX. I thought I was experiencing some sort of aberrant behavior and have reinstalled several times, even on a clean system this seems to be the situation. Is this an issue with 10.6.x, my hardware, or coreaudio in general or what? I'm using live 8.1 but I don't think this is an issue with live, but perhaps my hardware (?), or coreaudio in general.

Can anyone else comment on their buffer sizes and performance with high cpu usage (I'm mostly testing with the integrated cpu usage simulator, 80% seems impossible without setting a buffer size of 256 samples or more) and/or live cpu usage in general?

[visionize]

Look in the process tab of the CTRL ALT DEL feature on your computer this indicates all processes tht are currently running, maybe you'll see 2 live .exe running ,,,,causing the cpu usage of 300% ..close them by click on them and close process button...then start all over again with your set, its a problem at the moment...regards john

I have Windows 7 bootcamped with OX 10.6.2 (had same issue with 10.6.0 as well), on a new macbook pro. I've tried doing completely fresh installs but I can't seem to alleviate the problems I'm having with high cpu usage(?) while doing seemingly nothing. If I open a new project (1 midi track, 1 audio track, no clips, no instruments) on OSX I'm seeing roughly 13% cpu usage with onboard sound, 9% with my focusrite saffire. 44.1khz, 16-bit, stereo output only, no inputs, buffer size of around 256 samples. In windows task manager reports 0% until I actually do something. Just activating the i/o in os x seems to cause pretty large cpu usage increases. Is this normal? In terms of ableton live reported cpu available, OSX projects always report slightly more cpu usage than the same projects/settings in windows.

The real problem though, is that a combination of low latency, high cpu usage leads to terrible audio glitching/underruns on OSX for me. Experimenting with my saffire & onboard sound, it seems setting a low buffer size (sub 256 samples) causes issues with cpu usage over 50%. Just as a simple example, I can set the buffer size to 128 samples in windows and OS X, and on windows I can run the cpu usage simulator at 80% w/out glitching, but not on OSX. Anything under 256 samples (with 44.1khz/48khz audio) begins seeing diminshing returns. I'm able to use my saffire with a buffer size of 60 samples in windows w/out glitching at up to 80% cpu usage on the simulator, large projects are not a problem for me at all, and a lot of them use around 70-80% cpu. Switch over to OSX and there is no way I'm going to be able to work with them without freezing a lot of tracks.

I figured the performance would be roughly in parity across both platforms. Is this sort of high cpu usage (even with empty projects!) normal? Are there any tweaks I can do? I've tried setting all audio to 44.1khz 16-bit, disabled airport/bluetooth, killed dashboard, but I don't know what else I can do to increase performance on OSX. I thought I was experiencing some sort of aberrant behavior and have reinstalled several times, even on a clean system this seems to be the situation. Is this an issue with 10.6.x, my hardware, or coreaudio in general or what? I'm using live 8.1 but I don't think this is an issue with live, but perhaps my hardware (?), or coreaudio in general.

Can anyone else comment on their buffer sizes and performance with high cpu usage (I'm mostly testing with the integrated cpu usage simulator, 80% seems impossible without setting a buffer size of 256 samples or more) and/or live cpu usage in general?

[zeekay]

The issue I have is on Mac OS X, not Windows. I'm not seeing this sort of behavior on either platform.

If anyone has any real world experience with low latency audio hardware for OS X, I'd love to hear what sort of an interface would work the best in a high cpu usage yet low latency situation. Is there any interface that I can use at 48khz, with a 64 sample buffer or less @ 80% cpu usage on a mac w/out audio glitching/underruns? 96khz would be pretty amazing if it was usable but I'm not getting my hopes up