Corsair CMPSU-620HX 620 Watt Power Supply Review

Energy Efficiency

Did you know that power supplies play a major role when it comes to power consumption in desktop computers? I knew that it would make a difference, but not nearly as large of a difference as we found during testing. A 76W difference was noted on our AMD AM2 test platform, and after doing a little research, power supply efficiency is the reason behind the huge power consumption difference. The other critical thing when it comes to power consumption is Power Factor Correction (PFC).

The most efficient power supplies have Active Power Factor Correction (Active PFC). Active PFC power supplies use a circuit to correct the power factor, which means Active PFC power supplies are able to generate a theoretical power factor of over 95%. Active Power Factor Correction also markedly diminishes total harmonics, automatically corrects for AC input voltage, and is capable of a full range of input voltage. Active PFC is the more complex method of Power Factor Correction, so it is more expensive to produce an Active PFC power supply. Non-PFC power supplies are no longer recommended by many system builders and believe it or not, in Europe, power supplies are now required to have either active PFC or passive PFC.

Full Load Efficiency Ratings:

Power Supply Model	Efficiency %	Active PFC
Aerocool Zerodba 620	Not Listed	NO
Antec Neo HE 550	up to 85%	YES
Corsair HX620W	up to 80%	YES
Mushkin XP650	up to 73%	NO
OCZ PowerStream 600W	up to 73%	NO
OCZ GameXstream 700W	up to 80%	YES
Thermaltake ToughPower 550W	up to 80%	YES
Thermaltake ToughPower 750W	up to 85%	YES
Ultra X-Connect 2 550W	up to 71%	NO

According to the efficiency chart above, we should see the Thermaltake Toughpower 750W and the Antec Neo HE 550 drawing the least amount of power under full load. Since power savings is a huge deal in today’s market many are looking for a “green friendly” solution to the market. When looking at the below charts, keep in mind that the lower the number, the more efficient the PSU; thus, the more money you will save!

The Corsair HX620W power supply does very well against the seven other power supplies that we have tested in recent months. The HX620W power supply lives up to the 80% efficiency rating that it comes labeled with and places a solid third in our independent testing.