Introduction and Features

Can a popular PSU from yesterday power one of today’s power hungry video cards like AMD’s HD 2900 XT? Enermax says it can and we put their claim to the test.

Enermax recently threw down a challenge; they claimed that any of their mature Liberty series power supplies could power a modern high-end gaming system when fitted with the right cables.  Not a 1kW Galaxy mind you, but a tried and true Liberty 500W power supply unit.  And to prove the point, they sent us one of their updated Liberty DXX models and asked us to test it with a power hungry AMD HD 2900 XT video card.


Enermax Liberty DXX 500W Power Supply Review - Cases and Cooling 38


The original Enermax Liberty series is now two years old and included three different power supplies ranging in capacity from 400W to 620W.  The Liberty series from Enermax has earned a reputation for delivering very good reliability and stable power.  The updated Liberty DXX series includes four different models with output capacities of 500W or 620W and support for either NVIDIA SLI or AMD CrossFire.  What makes the DXX series new is the inclusion of modular cables that support the latest PCI-E 2.0 standard.


To promote ongoing product innovation, Enermax maintains its own R&D design team and manufacturing facilities in Taiwan with branch offices strategically located around the world with warehousing and distribution capabilities.


Enermax Liberty DXX 500W PSU Key Features:


  • 500 watts continuous power output (0-40°C ambient)
  • Meets Intel ATX12V 2.2 standards
  • Two +12V outputs (up to 32A combined)
  • Quiet 120mm cooling fan
  • Both hard wired and modular cables for maximum flexibility
  • Supports dual PCI-E graphic cards: NVIDIA SLI or ATI CrossFire
  • High-Efficiency 80% (30-100% load)
  • Active PFC with Universal AC line input
  • Compact chassis size (150 x 85 x 140mm)
  • 3-Year warranty 

Enermax Liberty DXX 500W Power Supply Review - Cases and Cooling 39


The Liberty DXX 500W PSU comes in a large retail box and includes a power cord, 6 modular cables, cable storage pouch, mounting screws, Enermax case badge, and a printed User’s Manual.


Establishing an accurate load is critical to testing and evaluating a PC power supply.  PCPerspective’s power supply test bench can place a precise 2,000 watt DC load on the PSU under test.  Each power supply is tested under controlled, real-world conditions up to its maximum rated output, using both 115 VAC and 240 VAC line voltages.  Our current suite of tests includes:


  • DC Load Regulation
  • DC Line Regulation
  • DC Cross-load (unbalanced load)
  • AC Ripple and Noise
  • Power Factor
  • Efficiency
  • Differential Temperature
  • Noise

Enermax Liberty DXX 500W Power Supply Review - Cases and Cooling 40


The Enermax Liberty DXX 500W power supply was evaluated on both features and performance.  A full range of equipment was used to test the power supply under controlled load conditions. 


  • (2) CSI3710A Programmable DC load (+3.3V and +5V outputs)
  • (4) CSI3711A Programmable DC load (+12V1, +12V2, +12V3, and +12V4)
  • FLUKE 87-III True RMS digital multimeter (Accuracy ±0.05%)
  • Extech 380803 Power Analyzer (Accuracy ±0.5% of full scale)
  • Hitachi V-650F 60 MHz dual trace oscilloscope (Accuracy ±3%)
  • Powerstat Variable Autotransformer, 1.4 KVA, 0-140 VAC
  • FLUKE  52-II digital thermometer (Accuracy ±0.3ºC/0.5ºF)
  • Extech Model 407738 digital sound level meter (Accuracy ±1.5 dB)
  • Custom Lian Li PC60 enclosure to simulate real-world operating conditions



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