Of course it all depends on your system and whether you are doing much data manipulation. We have a database table that has 2 crore (a new word to me, had to look it up!) records and alot of data manipulation in it. This qvd takes about 2.5 hours to reload. We have just upgraded systems and it use to take 4 hours to reload on the old system. I know this probably doesn't answer your question, but at least it gives you some comparison.
I don't know of any settings in QEMC that would speed it up.