BSOD Only when away from PC

I'm getting BSOD's after I go away for a bit. I have a feeling it may be related to some hibernate or power issues but I really don't know where to start. It's a brand new install of Windows 8. Attached are my dump files.

Thanks for the help.

Quick look indicates a "driver state change issue" associated with ACPI.sys. All Win 8 drivers look OK (and up to date) in device manager? Have you tired installing the latest BIOS update (just released 7/5/2013)?
Z87-PRO - Motherboards - ASUS