Looking at your system spec, it looks like its more than capable. My system can handle Preview (Auto) with no issue. I think that, maybe, you should 1, try restarting from the shutdown menu. If that doesn’t work, try a system restore to a few days before it happened. As a precaution, back up your important project to a USB Stick just in case. It might be an issue you may not know about. Hope this works.
~Amit
Loving VFX!