You need to provide more information to determine where to start looking for trouble, but I can offer some general guidelines to address from the get go:
*Be sure your computer has the latest and most up-to-date system drivers.
*Be sure graphics drivers are up to date and not BETA drivers.
*Be sure your HDD is operating correctly (using software like HDTune to monitor SMART data for brief indication of health)
*Be sure your OS is fully updated
*Check your filesystem for errors: In an elevated command prompt (CMD) type, 'chkdsk /f /r'. It will likely request to run chkdsk upon next reboot, select option for 'Yes'. Reboot your machine to run chkdsk.
*Check game caches if games are run via Steam (integrity check).
Beyond those simple things you should provide more information:
You mention 'microstuttering' but this phenomenon is generally relegated to CF/SLI setups, not single cards. That's not to say single cards don't stutter, it's just usually not 'microstutter' specifically. The stutters you face may be micro-type stuttering and not hard, rigid long stutters - this we'd need to know.
When does it happen? Length of stutter? All games or just the two you listed? Can you provide a short video of what's happening?
Anyways, the more information we have the better we can help you.