HP ProBook 4520S Ram - How To Upgrading Memory Card DD3 (1333 MHz) - YouTube
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HP ProBook 4520s Intel Core i3 CPU M 370 @ 2.40GHz, 4 GB RAM, 160 GB HDD with Microsoft Windows 10 Professional and Microsoft Office 2010 Home & Business.
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RAM upgrade (ProBook 4520s) - HP Support Community - 5656974