I've been having a significant amount of lag lately when writing articles in the visual editor. It usually happens when there's a pause and it attempts to save the progress, but it gets to be very frustrating when I notice a mistake and try to delete, only to have it not respond to any inputs. Lag bouts usually last for about 5-8 seconds per instance. It's been very difficult for me to make progress on certain articles, and it doesn't seem to change between browsers.
Begin typing, then pause for about 1 second, then try to continue writing. Lag and lack of input response occurs while the system is autosaving.