Can you check in your InDesign Preferences (CTRL or CMD K) under Interface and change Live Screen Drawing to "Delayed" instead of immediate.
I too get slow text files in InDesign - particularly using Tables that span multiple pages and also with using the feature of Span/Split Columns to span text across two or more columns.
Seems the more of these I have the slower the file goes.
It already is on "delayed."
If there is an Adobe technical supporter viewing this, I would like to send you a sample InDesign file with the above problem, but there is no way to attach it to this forum.