Are you using Alphavantage data provider? Alphavantage has limitation that it allows download of only 5 stocks data in a minute. So, it will take long time to download data of 1600 stocks.
If you are backtesting End Of Day data then use Yahoo! data provider, it will be much faster. If you want to test intraday data then I will advise to have patience or purchase Alphavantage data.
We will soon allow use of ascii (text) data so that you can use Stockalyze with other data providers that may deliver data in text form.