6.3.2 to 6.5.3 upgrade caused stutter in WMC Win7-VM

[Otter351]

Before I open the hood and make all sorts of troubleshooting and settings changes (which usually makes things worse), has anyone encountered this specific issue?  Nothing stands out at first glance, CPU usage does seem higher than normal but isn't being pegged and switching to the most current i400fx has helped decrease the stutter from every few seconds to every few minutes.  Assigning more cores to the VM doesn't help.  All playback is done through Xbox extenders, no passthroughs.  I'm reading that gamers have had similar issues, could it be the meltdown/spectre fix?  I'll probably revert to 6.3.2 for the time being (to keep the family happy) but I really would like the features of the current build.  Please note that I am a hobbyist and a baker by trade, if your solution requires me to go beyond the GUI...I'll likely not risk doing it :)