Lenovo recommends Windows.

Shopping for laptops and desktops
ThinkStation D20
  • Model Highlights
  • Part number: SNFK7MS
  • Processor
    Intel Xeon Processor E5620 4C ( 2.40GHz 1066MHz 12MB )
  • Operating system
    Genuine Windows 7 Professional 64
  • Total memory
    8 GB DDR3 SDRAM 1333MHz
  • Hard drive
    500GB
  • Optical device
    DVD Recordable
  • Form Factor
    Tower
  • Warranty
    Three year parts and labour