Enermax Infiniti 650W

Temperatures




While testing the Infiniti we encountered some very strange behavior in regards to temperatures. The exhaust temperature was similar at the various loads throughout testing, whether at room temperature or in the heat chamber. The secondary heatsink also stays at almost the same temperature in both environments, which means the power supply is not really dependant on the ambient temperature. Only the primary heatsink shows any significant changes in our heat chamber. At room temperature, it was only a few degrees higher than the ambient temperature; this pattern holds in the heat chamber as well, where it remains just a few degrees above ambient topping out at ~53°C. Needless to say, the temperature results are quite impressive.

Fan Speed


The fan behaves more like it's dependent on the load of the power supply rather than the temperature of the inside. The fan reached a maximum of 1500 RPM in our heat chamber before the safety feature kicked in to prevent overheating. While the room temperature was constant, the fan speeds up at higher loads in order to deal with the higher inner temperatures.

Acoustics


Even though the fan stays at a relatively low RPM level, the noise levels rise quite a bit, especially during the heat chamber test. We measure noise levels that are over 10dB(A) higher under heavy stress conditions than at room temperature. That means the fan really starts to make some serious noise at full speed. At the highest speed the fan is clearly recognizable since it produces 40dB(A) of noise at a one meter distance. On the other hand, in more comfortable operating environments the maximum 29dB(A) was hardly noticeable and not at all annoying. The larger fan with low RPMs does create some wind noise, but it is at a frequency that we did not find distracting and we would say subjectively the PSU is close to silent when operated at room temperatures.

After 20 minutes in our 50°C heat chamber, the Infiniti shut down with a clearly audible beep. Enermax states quite clearly that they prefer to have the PSU survive instead of burning up at high temperatures. We think the fan could spin a little faster than just 1500 RPM to help cope with the added heat (which of course would mean more noise) but that wasn't the case. One thing we might like is to get some warning beeps indicating that the PSU is about to overheat, thereby giving users an opportunity to save any critical documents and shut down gracefully rather than having the over temperature protection kick in. A hard shut down might save the PSU, but such actions aren't without potential side effects.