Power Supply Roundup: 730W to 900W

Cooler Master M850 - 850W

Cooler Master sent its high-end M850 power supply, which comes with a shiny mirror finish paintjob. A large 135mm fan on the bottom is responsible for cooling. There are plenty of holes at the back to serve as an exhaust. The unit lacks a power switch, which might be a concern for some people; however, since most people use power strips for their computer and peripherals this shouldn't be a major problem. The sticker on the AC jack was unnecessary, and the residue it left after removal is something we could have done without. Next to the jack is a small LED that indicates the status of the power supply. During our high temperature stress tests, the lamp glowed red the whole time; however, the PSU still worked fine as we can see from the results.

The label shows a total of six 12V rails which are rated at 18A (four) and 28A (two); however, the combined power is only 768W. This means there is around 10A per rail with combined power. This approach of writing whatever seems convenient on the label is a new trend, as though the manufacturers want to show there's no need to worry about power requirements. Incidentally, the 1000W version of this power supply has the same ratings for its 12V rails; the only difference is a higher combined power. The only way to manage this is with OCP. With six rails - and especially with two rails rated much higher than the others - it would have been great if Cooler Master listed the exact power distribution in the manual. They have provided this information for the 24-pin, 4-pin, and 8-pin ATX connectors, but not for the equally important graphics cards connectors.

Cables and Connectors

The cables are delivered in a nice, sleek bag that can be folded up. The cables are waiting patiently to come out and play. All are sleeved and the 6/8-pin PEG connectors differ in color. With ten Molex and eight SATA connectors the Cooler Master M850 is well equipped, and the length of up to 90cm is good for larger cases.

Looking inside will make any electronics enthusiast's heart beat faster. It's just a beautiful arrangement, and the two transformers will offer a great deal of power distribution. The primary side has a huge coil with two capacitors made by Nippon Chemi-Con and rated at 420V, 270µF, and 85°C (each). The secondary caps are made by Teapo. The soldering on the PCB for the cable management could be nicer, but the rest of the inside looks very clean. The heatsinks are well sized and thick. They are able to take a lot of heat from the attached components, and the space between the fins leaves enough room for air to reach the components on the PCB. Temperature diodes attach to the secondary heatsink on both sides - the two shrinking hoses where they attach to the fins are visible.