Exports can last hours depending on the number of files. Changing the format can decrease the time it takes.
There are two types of reports Windows Client (WC) can generate - a 'formatted' report and a 'raw data' report
Generation of a 'raw data' report is significantly faster because the output is not formatted. Generating a formatted report for 68 000 records is bound to be slow no matter how much RAM your computer possesses.