I notice that my timeline is having a serious performance issue during playback. The video preview is played with full quality without issue. Already update GPU driver. Already reset everything back to default. I notice this happen after the new update.
Did Ann's suggestion resolve the problem? If not, we never like to see performance issues. How bad is the lag? What video format are you working with? We'll need a few more details to help with this issue. Please see: How do I write a bug report?
I hope we can help you soon. Sorry for the frustration!