I have a Lenovo X220 laptop on which I've installed Windows 8 Consumer Preview. Sometimes though it'll get stuck using 100% of a CPU core though in the SYSTEM process, and there's nothing I can do to view the stack here to narrow it down to a specific component, because the system process is "protected".
The strange thing here is that the issue seems to be intermittent. 99% of the time everything works fine, but sometimes it'll just start doing this. Rebooting fixes the issue.
Process Explorer (after getting debug symbols turned on) says the following:
What steps might I take to troubleshoot this?