Multiple copies of data in datatable

Question

How many copies of data does the datatable store ?

I found this question from a year before but not a whole lot of details on there ? http://stackoverflow.com/questions/424598/what-is-the-memory-overhead-of-storing-data-in-a-net-datatable

Spefically, when do the copies get created? Are they flushed only on .Save() / .Update() ?

I have a datatable that listens to queue updates and updates only the cells that's are changed, this is never stored to db or disk, instead it's for display only

I'm looking to estimate the memory usage as we have potentially 5K-50K rows and 500-1000 columns but again only for display and constructed on the fly from column definitions stored elsewhere

Thanks