Back during the window a few years ago when Ultra was testing out pretty good I bought a 600W Ultra as an "upgrade" to my 400 watt. The thing was far from an upgrade and my system would not run stable with it installed. I was sent out a new 600W unit and that one did the same thing. I suggested that if the 600W model could not put out less then 400W reliably they needed to send me one that would even if it was a higher spec model. They did not agree with this idea and sent me a third 600W. What good is a lifetime warranty if the product is flawed? If anyone from Ultra is in here and wants to make this right with me by giving me one of these 850s as well please email me at [email protected].