OK I'm not sure what exactly did it, but a reboot, toggling the hardware monitors off and on, then a second reboot seems to have me back up and running.

I'm also having a problem with monitoring after upgrading to X57. Chipset, CPU, GFX, SSD are all unavailable (or -99.9C on my dashboard) and all of my virtual sensors are erroring out. Help would be appreciated! Edit: I should add that the sensors on all the aquacomputer devices are still working fine.