Snapshot: http://speccy.piriform.com/results/BFHOJWAXHZNnkPuerkioDXD
The above shows the mobo to have four (4) RAM slots.
http://www.biostar-usa.com/app/en-us/mb/introduction.php?S_ID=558#specification
The Biostar website for the mobo (above) shows two (2) slots