How to find out does my radeon 8870m uses system ram memory or it's own memory?

Hi, 

I recently bought the Dell inspiron 37371 laptop. After much trouble setting drivers for the radeon 8870m graphic adapter on windows 7, I decided to instal windows 8.1 to solve the problem. I instaled drivers and it seemed that everything worked fine(I downloaded free version of FurMark and msi kombustor, and checked it in afterburner). However I installed  TechPowerUp GPU-Z  and it tells me that my memory size is 0 and memory type GDDR5. How can I see wich memory my graphic card uses? Thanks ahead.