Coolmax CF-400 400W Fanless Power Supply
Price: $130.50

Though Coolmax is not as popular or well-known of a brand as the other companies in this roundup they should not be underestimated. Their offering, the 400W Fanless PSU has just about all the features the big guys have and offer their unit at as competitive a price as any other fanless model out there.

The power supply arrived neatly packaged, securely enclosed in bubble wrap. This method did the job perfectly but it is was not as nice as how the other companies shipped, with the PSU between two soft foam blocks that fit into one another. Even so the supply arrived in perfect condition. It came with a 24-pin converter so the supply can power PCIe boards properly according to ATX12V v2.01.

As with other fanless power supplies the Coolmax was overbuilt so it would be able to cope with the extra stresses of fanlessness. In addition to being quiet hefty the PSU has a thick aluminum housing, heavy duty transformers, and things like over-voltage, over-power, and short-circuit protection.

The CF-400 is heavily ventilated on each side except the bottom. It is has many more vents than any of the others in this test. This is good because it releases heat, but under a closer examination it could be a serious problem as dust will inevitably accumulate inside the PSU, especially since it does not have a fan to remove the dust. After looking at the other power supplies, which don't feature nearly as many vents, this method seems more like a poor man's solution to the problem of transfering internal heat.