Does it happen if you disable the sound driver ? (prevent it from loading or don't compile it at all if you are building your own kernels).
It seems to be working now. I could not convice the kernel image not to build with the sound modules so I simply erased the whole sound subtree from the /lib/modules and it's been working for thirty minutes now with the normal workload. Thanks! Just out of curiosity, what was happening? The sound is not supported on my iMac and the module was not being loaded. How can help the fact that I removed the sound modules? Now I'm ready to test the patches for fan control, actually that's what I wanted to do all along. Are they still the ones you mentioned a while ago?
First, you need the latest 2.6.14-rc5. Then, you can apply the patch that adds cpufreq support for the iMac G5 and the SMU based single CPU desktop. http://gate.crashing.org/~benh/ppc64-fx-freq-scaling.diff Then apply those 2 patches in that order: http://gate.crashing.org/~benh/ppc64-smu-partitions.diff http://gate.crashing.org/~benh/ppc64-smu-thermal-control.diff That's it. Now enable: CONFIG_WINDFARM_SMUandCONFIG_I2C_PMAC_SMU If you are using modules, you may have to manually load the whole bunch, especially the i2c SMU one which isn't requested (yet).
Eduardo.