Windows O.S. gives active applications priority over processes by default when assigning threads for execution. This is great for workstations but might not be optimal for database servers. One should periodically review the setting to ensure appropriate environment configuration.
Navigate through the control panel to find the advanced performance option. The screenshot below shows where to check on Windows Server 2012 R2.
Selecting "Background Services" causes windows to give background process and active applications equal processor resources.