Who write this shit?
RuntimeBroker.exe is a safe Microsoft process included in Windows to assist with Windows Store app permissions. With a light system footprint of more or less 5,000 K of RAM being used, it does not affect performance.
RuntimeBroker.exe is triggered by Windows Store apps. If there are no Windows Store apps open, this process won't run.
Unsurprisingly, I narrowed down my THIRTY PERCENT CPU USAGE and ONE-HUNDRED PERCENT DISK UTILIZATION to this ass process. And I wasn't (nor do I ever, to my knowledge) run "Window Store apps." Ugh.
Kill it, and we're golden.