I am using VLC to watch avi's and it was stuttering every few minutes.
As a workaround, you can add these files to the
Standard Shield provider (on-access scanning) exclusion list.
Left click the 'a' blue icon, click on the provider icon at left and then Customize. Go to Advanced tab and click on Add button...
You can use wildcards like * and ?. But be carefull, you should 'exclude' that many files that let your system in danger.