Just an FYI of what I've encountered, The RZ 1GHz kernel seem to have issues whether it be skipping in music, stuttering video, or not playing nice w/ SetCPU. Use the 1.1 or 1.2GHz kernels instead. Seem to play nice with everything, including SetCPU. Also, the 1.0GHz kernel has some weird 400.12MHz slot (or close to something like that) in SetCPU below 1GHz but above 900MHz in the "Info" tab. Skip the 1.0GHz kernel and choose one of the other ones. You can underclock both 1.1 and 1.2GHz kernels to 1GHz in SetCPU. Ran into this issue w/ both LGB posted and Peter's suggested RaidZero 1GHz kernels. I'm assuming they're the same version. Yes, I'm trying to push the RZ kernels cuz they've worked awesome for me and I've never had temp levels so low using any of his kernels!