I found how to reduce the issue in fax reception where the decoder resets timing. Setting the system performance to apps rather than background services seems to greatly reduce this issue.
When set to background, the system devotes almost double the time slice an app has in a cpu core and gives mostly equal preference to foreground and background apps, setting this to apps gives foreground apps precedence over anything running in the background, such as os calls, networking, and etc. Setting to background helps in compute intensive operations as it hives longer timeslices overall.
https://www.thewindowsclub.com/processor-scheduling-in-windows-7-8