FlowDocument Large Table Performance issues

Hello,

I've created a Flowdocument, consisting of one big table with ~20 cells and ~1600 rows resulting in performance issues.

First problem is, that rendering takes very long, im using FlowDocumentReader for this. When setting the created flowdocument as source of the reader i can see the number of pages increasing and when then switching to the scrollview the application freezes, takes much memory and finally crashes.

Is there any chance to improve the rendering performance?

Second problem is, when i then set the source of the flowdocumentreader to null again, the application freezes for ~1 minute with high cpu usage again.

Is there a better way of cleaning the document reader than setting the Document to null?

Thanks