A:Answer The spaces for additional drives are hidden behind the non-glass side pannel. If you take that panel off, you should see what looks like 2 metal plates that each have a thumb screw holding them in place toward the middle of the pc. those plates are, from what I can tell, where you would mount SATA SSDs. As for desktop HDDs, they are installed on the same side as the SSDs. There is a HDD mount tray at the bottom of the case next to the power supply.