The CS450M has been 80Plus Gold certified, which is outstanding for a product designed for mainstream users. It does not fail to deliver, reaching a maximum efficiency of 92.4% at 50% capacity and with a 230 VAC input. The efficiency drops down to 89.3% at 20% load and 89.5% at 100% load. If the input voltage drops to 110 VAC, the efficiency takes a hit of about 1% across the entire load range.
Despite the basic heatsinks and small size, the very high efficiency of the CS450M allows it to operate very quietly up to 50% load. If the load increases beyond 50%, the noise levels will begin to climb, reaching 30.4 dB(A) at 70% load, an audible but comfortable level, and up to 34.1 dB(A) at 100% load, which is highly likely to make the noise coming from the PSU noticeable over all other noise generated by the system.
The high efficiency of the CS450M allows it to maintain very low running temperatures across the entire load range. As the difference between the ambient and the exhaust temperature hardly is more than a few degrees, it is only possible to tell the difference only at heavy loads by sense alone. The temperature delta is just 4.2 °C at maximum load.