SilverStone Fan Compendium
 

While I can't comment on the 50000 hour lifetime spec, I can say that
after running each fan 24/7 I am confident that these fans will perform
admirably well into the future. All-in-all I can highly recommend the
FM123, the FN83, and the FM83.

http://www.overclockersonline.net/in...icles&num=1291