On Tue, Feb 28, 2012 at 7:12 PM, Rich E <reakinator@gmail.com> wrote:

Anywho, the latest nightly build is still running at around 17% cpu for me before ever opening a patch. It's just enough to make my fans hum. :)

I've attached a process sample from Activity Monitor, hope it helps track it down.

An interesting question. On my MacBook with OSX 10.5 Pd is sometimes running as much as 27% in 'idle' state. When Pd is started, dsp if off but the adc/dac are not. Only after turning dsp on, and off again, the adc/dac are off.

As you're on OSX, you can use the magnificent performance profiler Shark.app to get a better view of CPU load of functions. Most CPU time for adc/dac is consumed by DspFuncLib, AppleHDA and mach_kernel. Apparently, the system does a lot of processing on the audio stream without us asking for it. There's denoise, equalizer and fft functions amongst others. I don't think Pd can influence these routines, except by not using the adc/dac.

CPU load for adc/dac depends on hardware. Using an external audio interface reduces the load.

Katja