Samsung Galaxy Grand 2 SM-G7102 870 MB Ram Issue

I just recently purchased a new Samsung Galaxy Grand 2 SM-G7102 from Dubai. As per Samsung official and other mobiles sites like gsmareena showing this mobile have 1.5 GB ram but in my set total ram is showing 870MB, can anyone tell me what's the issue is this? See snapshot at: http://ift.tt/15z2UCc

Thanks.