Cooler Master Real Power Pro RS-850-EMBA (850W)
We already tested a Real Power Pro series product from Cooler Master in an earlier review. It was a 1000W unit and I was pleased with its good electrical parameters as well as quiet operation. Quietness is a fairly rare thing to find in a PSU with such high wattage. Let’s now see how the less powerful model from the same series behaves.
The PSU is large with a length of 180 millimeters. It is 40 millimeters longer than a standard ATX power supply, but this is not a problem. I doubt anyone would take a small system case to assemble a configuration that requires an 850W power supply.
The external panel of the PSU is perforated, the only blank spot being occupied by the mains connector. Besides everything else, this ensures good thermal conditions because the less resistance to the airflow the PSU elements offer, the more air can be pumped through the PSU case per minute at the same fan speed.
There is a LED indicator next to the mains connector. It is green when the PSU is turned on and red when the PSU is off or has evoked its protection. There is no On/Off switch here while a voltage switch is not required: the RS-850-EMBA is equipped with an active PFC device that supports the full voltage range from 90V to 260V.
The internal design is the same as that of the 1KW model except for the differently shaped heatsinks. The PSUs belong to one product series not only due to marketing reasons. They are indeed based on the same platform. It is quite a common thing, by the way. Having developed the circuit design and PCB of a power supply unit, the manufacturer rolls out several models with varying wattage that only differ internally in the ratings of certain components, in the size of the heatsinks, and in the performance of the cooling fan.
The PSU uses two power transformers. Although many manufacturers claim this to improve the stability of the output voltages, this is not exactly true. A single power transformer, with a twice higher rating and larger, would do just as well, but the dimensions of the PSU electronics are limited, especially vertically (the PSU case must accommodate a fan), so it is often expedient to install two smaller transformers than a single and large one.
The quality of assembly is high. I have no complaints whatsoever.
The PSU offers six 12V output lines but there is only one +12V power rail inside it; it has an allowable current of 60A (720W). There are six 18A current limiters on the PSU output which are set to comply with the safety regulations that require that there be no more than 240VA of power going into the PSU in case of a short circuit.
It’s not quite clear why the PSU label shows only the peak currents. It is more common to specify sustained currents and, additionally, peak ones.
The PSU offers the following cables and connectors:
- Mainboard cable with a 20+4 connector (49cm)
- CPU cable with a 4-pin connector (50cm)
- CPU cable with an 8-pin connector (50cm)
- Four graphics card cables with 6-pin connectors (49cm)
- Two cables with three Molex connectors and one FDD mini-plug on each (49+15+15+15cm)
- Two cables with four SATA power connectors (49+15+15+15cm)
Thus, this PSU can power up almost any modern PC configuration imaginable without adapters, even if it is a SLI or CrossFire system with two top-end graphics cards each of which has two external power connectors. The PSU delivers more than enough power for that. Our measurements show that such systems don’t even come close to the 850W mark.