Socket FM2 right?
DDR3-1866 or higher as its internal memory controler is 1866MHz, preferably a kit of 2 or 4 modules like for example a Crucial BallistiX Tactical 8GB DDR3-1866 CL9 kit (2x4GB)
And actualy you should look at the Motherboard manufacturers site as they usualy list what memory is compatible, but i wouldnt go under 1866MHz, higher is ok, it will than be clocked down to 1866MHz.
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Notebook specs: AMD Athlon X2 QL-64 2.1Ghz, AMD 780G Chipset, ATI Mobility Radeon HD4570 512MB, OCZ 2x2GB DDR2-800, WD Scorpio Black 320GB, 15.6" 1366x768 Screen.