StarTech.com WattSmart 650 W can really deliver 650 W at a room temperature of 50º C. This is really good.

The number of cables it has – two 6-pin PCI Express auxiliary connectors for video cards, six SATA power connectors and six peripheral standard power connectors – makes it a good product even to high-end users building a PC with a RAID array, two or more optical units and two video cards in SLI or CrossFire configuration.

Another good thing about this power supply was its efficiency, between 82.2% and 86.2% depending on the load.

Its cooling system showed to be very efficient, keeping the power supply at the same temperature level found inside our hot box (usually during our tests the power supply temperature is between 2º C to 5º C higher than the temperature inside our hot box).

But the main problem with this unit is the level of electrical noise. When pulling 650 W it practically touched the 120 mV limit for the +12 V outputs. By pulling just a little bit more than 650 W from this unit noise level at +12 V outputs surpassed the 120 mV limit, and the problem is that users don’t have a way to know this without reading a review like ours telling them that this happens.

On the other hand, this power supply won’t explode if you try to pull more power that it can handle.

At the end the dual-transformer design didn’t help this power supply. We’ve seen other power supplies in the 600-700 W range that have only one transformer and are able to deliver its labeled power at 50º C and have a far lower noise level.

Unfortunately because of its very high noise level we can’t give this product an award seal.