The Cougar RS 650 W is, in reality, a 600 W power supply, as it explodes if you try to pull more than 600 W from it. We tested two samples, with the same results.
Users buying this unit probably won’t pull anywhere close to 600 W or 650 W. We believe that manufacturers must label power supplies with their true wattages. Therefore, we can’t recommend this unit.
It is important to understand that the manufacturer may not have done this on purpose. The RS 650 W looks like a textbook case of a power supply that was labeled at a room temperature of only 25° C (which we believe doesn’t represent a real-world scenario). As the ability to deliver current (and, thus, power) drops as temperature increases, it can’t deliver its labeled power at high temperatures. In cases like this, the power supply over power protection should have kicked in, which didn’t happen with the reviewed power supply.