I assume you meant 2x4 RAM in Slots 1/3. If so yes you can but i strongly advise using another of the same kit you are already running to avoid any issues. This means you will need another 2x4 kit of what you are running right now which will run 4x4GB in total across slots 1-4. If you don't know what kit you currently have i suggest running this to find out > http://www.userbenchmark.com/Software
It should only take about 60 seconds to complete and will list your primary specs including RAM model/speed/latency,etc. Hope this helps
I assume you meant 2x4 RAM in Slots 1/3. If so yes you can but i strongly advise using another of the same kit you are already running to avoid any issues. This means you will need another 2x4 kit of what you are running right now which will run 4x4GB in total across slots 1-4. If you don't know what kit you currently have i suggest running this to find out > http://www.userbenchmark.com/Software
It should only take about 60 seconds to complete and will list your primary specs including RAM model/speed/latency,etc. Hope this helps