datatable/dataset and binding questions

what i've know already is sqldatareader (or datareader) is an open connection mean u still connect to database. while datatable or dataset don't.

so datatable and dataset is closed connection means that the cursor is locally and the data is saved in client RAM.

what i'm asking is,
what is the different with
1. if i bind the datatable or dataset to a control
and
2. iterating through item in datatable/dataset to populate data to control mannually

considering in RAM issue?