AMP Series 650W 80PLUS Gold

Within a week of installation in a single system setup with loads well below advertised - fan never kicked in during usage, my workstation started randomly powering down. Enough power would be supplied for the system stand by and LED lights, so restarting would appear fine until the next shutdown. Connected with Phanteks support via Amazon.com and was advised over the phone to try and swap the 24 pin ATX cable with the secondary one that comes in the box for dual system setup. I did so, and correlated with that or not, the power downs got worse over the next few hours until finally the system would not boot anymore. Physical inspection of the unit from outside did not reveal any overheating or unusual odors - whatever the issue. Did not notice voltage fluctuations while in BIOS before the failure, so at this point I could not rule out the cause being other hardware (e.g. motherboard). I went in and purchased an EVGA Supernova 1200W from a local store, which happened to have a unit in stock, replaced the Phanteks, and behold - the system now powers up again and is stable, even though the EVGA has older cable design and is a much larger unit, and costs about $100 more Overall, I would have given this product a high rating due to the creative design (dual system support), but I would strongly caution against using this beyond experimentation. Such a dramatic failure points to either manufacturing or design issues, and judging by spotty reviews here and other retailers, I don't believe I just got unlucky.