Spire has done a good job with their Rocketeer 500W Power Supply Unit. Performance on the unit was stellar, easily handling SLI and Crossfire on two different systems. With more and more dual video card systems sold today, SLI or Crossfire is an important consideration when looking at a power supply. Stability was excellent, with no crashes with even the most demanding applications.
FULL STORY @ MOTHERBOARDS (http://www.motherboards.org/reviews/hardware/1595_1.html)