To corroborate Mr. scook, my Mac Pro (Win10, Win7) with 12-cores/24-threads is a very happy CbB machine. 

bitflipper
Some background task is monopolizing your system resources. I doubt it's the synth, or any other thread within the DAW. That it goes away while running Task Manager is troubling, as that is behavior a clever virus might exhibit.
 
Download a copy of Process Explorer from Sysinternals if you don't already have it. It will show far more information than Task Manager. While you're there, also grab a copy of Autoruns to see what's automatically starting up when you boot. Another good sleuthing tool is CurrPorts from Nirsoft, which reveals all your network connections and what processes are using them.
 

Bit... is there a resource that gives any info on what’s safe to remove from autorun at boot up? Sometimes I’m not sure what can/shouldn’t be turned off.

Thanks for all the assistance fellas! Each and everyone of you had something useful to offer. Turns out my PC had some viruses and malware causing issues. So @Bitflipper, you were right on  the $. And I will def take a closer look with those apps you recommended. I think I had registry conflicts too (ughh). I ended up just performing a fresh install of Windows 7 Pro. After 48 hours of re-installing (everything) thus far, all seems to be on the up & up. I'll keeping monitoring this midi issue. 
 
 
@Wookiee - Was monitoring System Performance. My beefed up HP Z800 Server PC seems to handle audio/video rendering well. 
 
@msmcleod - No. It was def Windows 7 acting up & not Cakewalk's monitoring system (this time) becasue its 100% working now.
 
-Lee