Seasonic is one of the most experienced PSU manufacturers out there, since they started manufacturing PSUs quite some time ago. Actually Seasonic entered the PSU market in 1980, to support the legendary Apple II and the first IBM PCs. After two and a half decades and many innovations and significant milestones Seasonic was the first manufacturer that won the 80PLUS efficiency certification, in 2005. Four years later, in 2009, the hi-end X PSU series hits the market and obtains numerous awards and top ratings from every expert PSU reviewer.