Seek Help for table merging from dataflow

Hi There, 

All the data are downloading from dataflow, they are sales data from past 3 years and current year. When I try to append all the table, it took me an hour for refresh. If I just download the table sepeartely, I can refresh much more faster. What can I do to speed up the appending pocedure. Thank you.

Single one of appending took too long time for loading.

Sammy Chu