Since the VS will recognize only up to 8 partitions of 10 GB each, adding a second hard drive (in case it works, mind you. I seem to remember FalconEddy suggesting in pretty strong terms that it will not, and he is the ultimate digital specialist here... ) will not benefit you all that much. It would be like putting a 200 GB drive and wondering why you can use only 80.
Anyways. I wouldn't mess with it.