I have a rig built on that mainboard and have had no problems with it. I have it running on my old Sapphire HD 5850 Crossfire and runs great. My main rig still runs on an MSI 890FXA-GD70 as the performance difference just was not there to upgrade to a 990 based mainboard.
The fact that you can choose to turn off or turn on a core easily doesn't really impact gaming performance.
The thing that matters most is Clock Speed x IPC and that has nothing to do with turning on or off the 3rd - 6th cores.
If anything, the program itself makes your computer some tiny % slower just because you are using and compounds the problems the FX chip has in general.
"Additionally, parking CPUs can potentially reduce core thrashing - when a thread is swapped between cores unnecessarily, causing a performance hit."
"This option has *something* to do with how aggressively the Windows scheduler will park CPUs based on over-utilization of parking in the past. In other words, if it has been parking them too often, it will 'ease up'."
"Additionally, I've found Windows CPU Parking to be excessively aggressive by default. In one test bed, an AMD Bulldozer platform (8150), the scheduling problems were *very* apparent. Turning off CPU Parking causes an immediate boost in responsiveness, particularly for the virtual machines and multimedia applications."