Hi Rafael,
My laptop is a MacBookPro8,1 with i7 processor, 8GB
ram, built-in intel
HDA soundcard
For Intel HDA a tweak is often required to get good performance. See:
http://apps.linuxaudio.org/wiki/intel_hda_realtime_howto
Ignore the kernel recompile part, but note the issue with mixer capture
switches if using jackd in full duplex mode.
Codec: Cirrus Logic CS4206
Try adding these options at the end of /etc/modprobe.d/alsa-base.conf
options snd-hda-intel model=mbp55 position_fix=1 enable=1 index=0
The mbp55 value for CS4206 is found near the end of:
http://www.kernel.org/doc/Documentation/sound/alsa/HD-Audio-Models.txt
Then reboot and see if JACK performance improves. You should be able to
get 64 frames/period x 3 periods/buffer @ 48KHz on this hardware.
Cheers!
Daniel