Lenovo ThinkCentre M83 SFF(small form factor) Business Level Desktop: Core i3-4150 3.5GHz 500GB 4GB DVD-RW Windows 7 Professional Upgradable to Win 8 Pro ThinkCentre M Series continues to expand cost- and management-control capabilities, providing enterprise users and IT managers with smarter ways to be more productive. Intel Core i3-4150 3.5GHz 500 GB 7200 rpm Hard Drive with DVD+/-RW 4GB DDR3 memory, Maximum support 16GB. Windows 7 Professional Upgradable to Win 8 Pro ; Also Eligible to upgrade to Windows 10 for free.