So, what has happened is "something" on my PC changed, which now leads me to have 20-30% CPU usage from Hardware Interrupts and DPC's.
I've narrowed the culprit down to ACPI.sys drivers, but none of them are able to be updated. In particular ACPI.sys!OSNotifyDeviceWake is proving to draw a ton of power. But even after disabling all power control in Device Manager, choosing a different power plan, and other annoying tidbits, I still haven't been able to fix my problem.
I hope someone here can help, as getting help elsewhere started out great, but is now just a waiting game