Introduction

Enermax has been a big name in the power supply business for many years. They produce a wide range of consumer and professional power supplies for personal or server computer systems. The new Active series of power supplies tries to address the issue of noise in power supplies. As the wattage increases on power supplies, so does the heat. In order to reduce the heat, high-speed cooling fans are needed to keep a steady stream of air moving through the unit. The problem is that the fans generate a large amount of noise that is disruptive to the computing environment.

The Unit

EG651P-VE Box Contents

The EG651P-VE features a number of items to try and help reduce the amount of noise generated by the fans in the power supply. The most prominent of them is the manual speed control for the 80mm fan. On the back of the power supply is a small knob that can be used to vary the speed of the fan from 1200 to 2500 rpm. The internal 92cm fan is a thermally controlled fan that has its speed adjusted based on the temperature of the power supply. Both fans are twin ball bearing units to help reduce vibrations while operating.

EG651P-VE Back Showing Fan Control

When the fan is set to its lowest speed, the power supply fans are essentially silent. It is very difficult to hear the fans compared to the other components that might exist in the system or cooling fans in the computer case. At the full speed setting, the power supply does become audible, but its noise levels are still very acceptable. In many cases, the fan used on the heatsink or the case cooling fans will still generate more noise.

There are a large number of connectors with the unit. All totaled, there are eight 4-pin molex connectors, two 4-pin floppy power connectors, ATX power connector, ATX12V connector, an AUX connector and an "Extra" connector. All of the power cords are long enough to support the unit being inside of a full sized tower case and still being able to reach all the devices in the system. This means that there are a lot of wires. Placing this power supply into a case smaller than a mid-tower case is not advised as the wire bundles would end up getting in the way. The motherboard ATX and ATX12V connector wires are contained in a plastic mesh sheath to make it a bit easier to manager the wires.

Power Specifications

Below is a photograph of the label on the side of the EG651P-VE power supply showing the power ratings of the unit:

EG651P-VE Power Label

Based on the information listed on the label, the actual 3.3v and 5v must be sharing the same rail. Based on the label information, the 3.3v and 5v lines individual can run at 119 and 180 watts, but the maximum listed wattage is 200 for the pair. The 12v rail has a wattage rating of 432 watts. If you calculated the individual voltage lines together based on their ampere ratings, the power supply would theoretically supply approximately 732 watts, well above its peak rating. Thus, based on the 200W maximum listing for the 3.3v and 5v combined with the 12v line, the maximum output is a more realistic 632W. Of course that is just the maximum peak rating and the continuous wattage should not exceed 535W which shouldn't be a problem for most consumer based platforms.

Testing

Below is the hardware that was used in the system containing the EG651P-VE power supply for testing:

I didn't have any means for testing the actual loads on the line to verify the wattage, but at 535 watts with a peak rating of 650 watts, it would require a lot of drives, cooling fans and other accessories to really try and max out the power supply. Therefore the tests instead are being done to verify the voltages across the individual rails in the power supply to ensure clean power to the components.

Readings of the voltages levels were done via Mother Board Monitor 5 running during the whole process. The high and low voltages were then taken from the tests and reported. Since the power supply has a manual speed control for one of the cooling fans, the tests were run twice at the lowest and highest fan speed settings. The system was stressed for approximately 30 minutes straight using SiSoft Sandra's Burn-In process. In addition to the high and low voltages for both the minimum and maximum fan speed settings, the CPU and chipset readers were also taken to see how the temperatures inside the case varied for the fan settings. The system was allowed to cool for approximately two hours between tests.

The temperature differences between the fan adjustment being on the lowest and highest setting did not make a significant difference. If the system were stressed for a longer period of time, the higher fan speed setting may very well increase the gap between the temperature readings.

Voltage levels between the fan settings were essentially identical with only the -5v line showing a slightly variation. The amazing part is the percentage difference between the rated and actual power levels. While the -5 and -12v rails were as high as a 7.6% off from their rated levels, the +3.3v, +5v and +12v levels were typically between 1.2% and 4.2% off during extreme loads. This is well within the ATX specifications and should provide extremely stable voltage lines to the system components.

Conclusions

Overall the Enermax/WaveSonic EG651P-VE power supply is a very high quality power supply that anyone with a server or high-performance system should consider. While it would be nice to see them separate the 3.3v and 5v voltages to separate rails to improve the overall wattage ratings of the system, the voltage levels remained very steady at high loads. Users will not need to worry about power fluctuations impacting their systems stability. Overclockers in particular will be very pleased with the stable voltages that can allow them to really push their systems. The adjustable fan is an interesting feature, but overall it didn't really seem to improve the cooling performance or dramatically decrease the already low noise levels. Users looking for a silent PC can leave the unit at its lowest setting and pretty much will never hear the power supply fan. This power supply is not recommended for smaller desktop cases due to the amount of wires running from the unit.

Manufacturer's Site