microbrews

Disabling folder caching also fixed it for me, but I'd like to see if there's a way to still use that plugin without it hammering the CPU.

I am preparing to build something very similar to what you have. I've read in a few places that the JMB585 controller does not support higher C-states, so what I'm planning to use is the ASM1064 (same idea as ASM1166 but 4 ports instead of 6), and flashing it with updated firmware if necessary -- I've read that powertop auto tune will cause it to malfunction when it has older firmware.