DXDiag shows approx total memory 6GB, but my GPU is 2GB

stardustjinx

Prominent
Dec 5, 2017
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I have Asus/Nvidia GT 730 (2GB) GPU and 8 GB of RAM, but whenever i open up the DXDiag it shows approx total memory 6GB's instead of 2, and seems I'm not using 8 GB of RAM properly either. Is there way to fix that?
(Sorry for my bad English and sorry if i posted this on the wrong place, i'm new here :( )

My PC specs;
https://ibb.co/hexQXw
https://ibb.co/jhdXCw