Enermax Liberty ECO 500w ATX PSU Page: 1

EnermaxEnermax is one of those few companies in the PC scene that requires no introduction. With products such as the Galaxy 1000w and Infiniti range under their belts, Enermax has on several occasions made a profound impact on the PSU market and helped shape it into what it is today. A few months ago I was lucky enough to review a pre-release sample of their latest PSU - the Revolution 1050w. The unit didn't disappoint and walked away with OC3D's "Best in Class" award, proving itself to be a worthy successor to the now ageing Galaxy series.

However today Enermax have sent over a far more modest 500W PSU from their Liberty ECO range. The original Liberty range has been around for some time and in fact was one of the very first PSU's from Enermax to 'break the mould' with it's glossy metallic paintjob and modular connectors. OC3D first took a look at the original Liberty 620w back in 2006 and despite having a rather limited test setup at the time, it was clear that the Liberty was an extremely competent PSU that combined copious amounts of the three P's: Price, Performance and Presentation.

For the Liberty ECO, Enermax have turned their attention to improving the economic and ecological aspects of the original Liberty by increasing efficiency while also bringing many of the other features bang up to date. Below is the full feature list taken from Enermax's website:

• 80PLUS® efficency - 80-86% efficiency @ 20-100% load. Compliant with 80 PLUS® efficiency requirements.
Fit4Server -12Pin modular design for possibly upcoming new CPU's and graphics 10 and/or 12Pin connectors.
• Non-Stop @ 40°C - Non-Stop industrial class performance at 40°C/104°F ambient.
• DXX ready! - For PCI Express 2.0 / DXX next generation graphic cards with 6+2P (8P) PCI-E connectors.
• Intel ATX12V v 2.3 - ATX12V v2.3 support for latest Intel® Core 2 Duo™/Quad™/Extreme™/ i7™, and AMD™Athlon™ 64X2/X4 & Phenom™X3/X4 and SLI™ or CrossFireX™.
• EMC & Safety - Full-scale electromagnetic filtering protects your system against radiation interferences. (CE EMC EN61204 compliance)
• SpeedGuard - Advanced fuzzy logic 12cm fan speed control for optimal cooling and minimum noise. (Patented)
• AirGuard - Patented air-inlet with optimal aero-dynamical design reducing noisy air turbulences.
• SafeGuard - Industry-leading septuple protection circuitry with world's first dual UVP(AC & DC), OCP, OVP, OPP, OTP & SCP protects your system.
• Worldwide compatible - 100-240VAC in with automatic adjustment and active PFC for global usage.
• Compact size - Dimensions (W x H x D): 150mm x 85mm x 140mm
• Warranty - 3 years vendor warranty

Aside from the increased efficiency, Enermax have also kitted the Liberty ECO out with a long list of safety features which include the usual suspects such as Over Volt Protection and Over Current Protection. Interestingly Enermax's PowerGuard system doesn't make an appearance on the Liberty ECO; which is kind of a shame as PSU's with fancy LED's and buzzers always gives me something extra to talk about.

Also of interest in the specs list is the ATX v2.3 connectors which provides support for the latest hardware along with Enermax's certification that the Liberty EC can provide it's full output power at up to 40°C. This should make things a little interesting when we stick it inside our 50°C oven later on in the review!

Enermax Liberty EC 500W Rail Layout
DC Output +3.3V +5V +12V1 +12V2 +12V3 +12V4 +12V5 +12V6 -12V +5VSB
24A 24A 24A 24A - - - - 0.6A 3A
Max Power 130W 456W 7.2W 15W

Things have been kept nice and simple in the rail layout department with two +12v rails capable of producing 24A each and a maximum combined output of 456W (38A). This gives the Liberty ECO plenty of grunt to deal with a single high-end graphics card or a pair of mid range cards configured in SLI/Crossfire. 

Similarly the +3.3v and +5v rails are also rated at 24A each, but this time with a maximum combined output of 130W. This is slightly lower than some other 500w PSU's we've tested recently (for example the OCZ ModXStream Pro 500w), but for the modern PC system having more power available on the +12v rails is far more favourable.

Enermax Liberty ECO 500w ATX PSU Page: 2
Packaging & Appearance

There's no better way to say 'Eco' than by use of the colour green and therefore it's no surprise that Enermax have chosen this to be the primary colour of the packaging used on the Liberty ECO. The front of the box keeps things plain and simple with a two-tone colour scheme and a picture of the unit, while the back of the box carries most of the information including the power distribution chart and graph showing the efficiency of the unit through the various load levels.

Enermax Liberty EC 500w Box Enermax Liberty EC 500w Box Back
The sides of the box are also packed out with information too, with printed diagrams detailing how many connectors are included with each of the Liberty ECO models (400w, 500w & 600w),  and a larger version of the power distribution chart for those who didn't happen to have their glasses handy to read the one on the rear of the box.

Enermax Liberty EC 500w Box Side Enermax Liberty EC 500w Box Side
Taking a look inside we can see that Enermax has placed the Liberty ECO inside a bubblewrap bag to protect it from scratches and minor damage. This is what I'd consider to be the 'bare minimum' protection for a PSU in transit, but considering that the Liberty ECO is aimed more at the mid-range market any elaborate packaging such as large styrofoam blocks and velor drawstring bags would just unneccesarily bump up costs.

Enermax Liberty EC 500w Box Open Enermax Liberty EC 500w Contents
As you'd expect for a 500w unit, the Liberty ECO is quite compact. Measuring in at 150x85x140mm there should be no issues fitting it in any smaller ATX cases and some HTPCs. The finish on the unit is a matte black powder coat with a rough textured surface. While this feels quite scratch resistant, it doesn't carry the same aesthetic appeal as the gloss black and metallic gold flake finish of the original Liberty Series.
Enermax Liberty EC 500w Top Enermax Liberty EC 500w Front
As a result of its compact size Enermax have been restricted to using a 120mm fan inside the unit. Had the unit have been a few mm longer Enermax could have pottentially shoe horned in a 135mm fan to help increase cooling performance much like on the Infiniti series. Of course, size isn't everything so we'll take a closer look at the make, model and specifications of the fan in a while.

One thing that certainly hasn't changed throughout the entire Enermax PSU range is the use of gold fan grills. This seems to be somewhat of a tradition for Enermax, and although the 'fake' yellow gold look is something that is often classed as 'tacky' in recent years, it does give the Liberty ECO a sense of uniqueness.

Enermax Liberty EC 500w Side Enermax Liberty EC 500w Fan
Of course, as the saying goes "beauty is skin deep" so let's move on to the next page where I whip out the screwdriver and attempt to get beneath the skin of this modest looking unit.

Enermax Liberty ECO 500w ATX PSU Page: 3
Cables & Internals

Despite the Liberty ECO being a 'modular' PSU, both the ATX and EPS-12v connectors are hard wired into the unit. This is actually quite a common practice among most modular PSU manufacturers as both of these cables will be required at the very minimum to power a PC system. Hard wiring these connectors into the PSU also reduces the chance of poor connections or increased resistance due to an ill fitted modular plug.

Enermax Liberty EC 500w Hard Wired Enermax Liberty EC 500w Modular Plugs

Following on from the gold fan grill tradition, Enermax have also re-used the gold laced cable sleeving seen on most of their previous units. Whether this appeals to you or not is certainly a matter of taste, but I guess you can't blame Enermax for wanting to break away from the boring black stuff. One thing we can blame them for however is just how much bare wire is on show at the end of each connector. Granted that some of this is unavoidable as certain connectors such as the ATX spread out significantly towards the end, but other modular connectors such as the 'joined' PCI-e cables would be much better sleeved individually and right to the tip.

Enermax Liberty EC 500w ATX Enermax Liberty EC 500w PCI-E

Enermax Liberty EC 500w Cables Enermax Liberty 500w EC Bag

A total of 4 modular cables are included with the 500w version which is actually quite poor considering the unit has connectors for up to 5 modular cables. In fact, this has to be the first time ever I've seen a modular PSU that doesn't come with enough cables to utilise all of the available connectors on the PSU. To compound matters further, one of the cables has a rather daft arrangement of SATA and Molex connectors on a single cable which might not suit all system layouts. A full list of connectors can be seen below:

Enermax Liberty ECO 500W Connectors
 ATX Connector Native 1x 24 Pin
 EPS-12v / P4-12v Connector(s) Native 1x 4+4 Pin
 Molex Connectors Modular 5x
 Floppy Disk Connectors Modular 1x
 SATA Connectors Modular 5x
 PCI-E Connectors Modular 2x 6+2 Pin
Moving on to the internals, the Liberty ECO is extremely tidy and spacious with plenty of room between each of the components and all cables entering the unit bunched tightly with zip ties. Two yellow transformers take centre stage in the middle of the unit, with the smaller of the two being responsible for the 5VSB (Stand by) rail and the larger one for everything else. Cooling comes in the form of two fairly small black aluminium heatsinks that run in parallel down ¾ the length of the unit.

Enermax Liberty Eco 500w Inside Enermax Liberty EC 500w Inside
An EMI filtering circuit has been installed just behind the AC inlet on a rather tidy PCB. This should help to keep any internally generated noise from the MOSFET's and other components contained within the device, while also preventing any external AC line noise from entering the PSU.

Enermax Liberty EC 500w Filtering
The primary capacitor is manufactured in Japan by Panasonic Corporation and carries a specification of 330uF / 400V / 85°C.  This may not be quite as high spec'd as the 105°C capacitors used in mid-range units by companies such as Corsair, but  it's still far from poor quality, and should perform perfectly fine inside a 500w unit.

At the output end of the unit (image below-right) several capacitors manufactured by jP (CE-TUR series) can also be seen in several sizes and specifications.

Enermax Liberty EC 500w Caps Enermax Liberty EC 500w Caps
Cooling comes in the form of a 120mm fan labeled up as an Enermax EB122512H. This fan is rated at 0.30A (12v) and is automatically controlled by the on-board fuzzy-logic controller which monitors both load and temperature levels to determine the best fan speed. Further specifications for the fan are extremely thin on the ground with no official dbA or CFM statistics being listed anywhere on the Internet.

Enermax Liberty EC 500w Fan Enermax Liberty EC 500w Fan

Now that we've dissected our subject, let's attempt to put it back together again ready for testing over on the next page.

Enermax Liberty ECO 500w ATX PSU Page: 4
Simulated Load Testing

To provide our readers with the most accurate results, Overclock3D uses a professional grade SunMoon SM-268+ ATE load tester capable of placing a sustained load of 1690w across a total of six rails (including +5vsb and -12v) on the PSU. Unlike our previous resistor-based load tester, the SM-268+ gives us the ability to adjust amperage loads in increments as small as 0.01A while also measuring voltages and wattage readings on-screen.

During today's tests, we will be placing the Liberty ECO 500w under 25%, 50%, 75% and 100% load levels at both room temperature and inside a hot box regulated to a temperature of around 50°C. Additional cross load tests will also be performed under these conditions to simulate how the PSU would perform with a heavily uneven distribution of load.

Enermax Liberty ECO 500w SM-268+ Results @ Room Temp
  +3.3v +5.0v +12v1 +12v2 +5vSB -12v AC Watts /
 DC Watts
 Efficiency Intake /
Δ Temp
Test 1
3.75A 2.50A4.16A4.16A 0.75A 0.15A 155w /
 85.16% 23.3°C /
3.38v5.02v12.24v12.22v5.07v -11.83v
Test 2
 7.50A 5.00A 8.33A8.33A 1.50A 0.30A 308w /
 85.38% 24.3°C /
3.36v4.98v12.20v12.15v5.03v -11.81v
Test 3
11.25A7.50A12.49A12.49A 2.25A 0.45A 466w /
 84.12% 24.6°C /
3.34v4.94v12.16v12.13v4.98v -11.79v
Test 4
 15.00A 10.00A 16.66A16.66A 3.00A 0.60A 630w /
 82.22% 25.0°C /
3.32v4.90v12.12v12.09v4.92v -11.81v
Test 5
19.70A13.00A0.50A0.50A0.75A0.15A 190w /
76.31%25.0°C /
Test 6
 3.00A 5.00A 19.00A19.00A 0.75A 0.15A 583w /
83.87% 25.7°C /
3.37v 5.01v11.90v11.92v5.03v -12.10v

Looking first at the voltage output in standard Tests 1-4 all of the rails manage to stay extremely solid with no more than 0.13v fluctuation being exhibited on any of the rails. This is especially impressive considering in Test 4 the unit was running slightly out of spec at 518w. Efficiency was also above average with ~84-85% being seen in the Low,Medium and High tests and the unit only dropping to 82.22% efficiency when fully loaded.

Moving on to the first set of cross load results in Test 5, things do seem to take a slightly southwards turn with the +5.0v rail dropping to 4.78v and the +12v rails hitting a rather nasty 12.81v. Additionally the efficiency also plummets to a pretty dire 76.31% showing that the Liberty ECO really isn't geared up to deal with such heavily unbalanced loads.

However, Test 6 gives the Liberty a chance to redeem its self with all voltages going back to fairly normal levels and efficiency levelling back out at 83.87%. This is especially good as most modern cross loading situations are likely to be heavily weighted on the +12v rails (due to high powered GPU's) much like the Test 6 configuration.

Enermax Liberty ECO 500w SM-268+ Results @ 50°C
  +3.3v +5.0v +12v1 +12v2 +5vSB -12v AC Watts /
 DC Watts
 Efficiency Intake /
Δ Temp
Test 1
3.75A 2.50A4.16A4.16A 0.75A 0.15A 155w /
 85.16% 49.5°C /
3.37v5.03v12.22v12.20v5.07v -11.83v
Test 2
 7.50A 5.00A 8.33A8.33A 1.50A 0.30A 308w /
 85.38% 50.5°C /
3.35v4.99v12.18v12.14v5.02v -11.83v
Test 3
11.25A7.50A12.49A12.49A 2.25A 0.45A 467w /
 83.72% 50.4°C /
3.33v4.94v12.14v12.10v4.97v -11.82v
Test 4
 15.00A 10.00A 16.66A16.66A 3.00A 0.60A 634w /
 81.54% 50.9°C /
3.31v4.90v12.08v12.01v4.91v -11.82v
Test 5
19.70A13.00A0.50A0.50A0.75A0.15A 191w /
75.91%50.7°C /
Test 6
 3.00A 5.00A 19.00A19.00A 0.75A 0.15A 584w /
82.70% 51.0°C /
3.37v 5.02v11.82v11.78v5.02v -12.14v

Performing exactly the same battery of tests again; only this time at 50°C took its toll slightly on the Liberty ECO with the most noticeable differences being in tests 4 and 6 with voltage drops of between 0.08 - 0.14v on some of the rails. Interestingly, efficiency levels hardly changed despite the increased heat, and temperature differences from Intake to Exhaust also remained quite similar.

Enermax Liberty ECO 500w Scope Results @ 50c
  +3.3v +5.0v +12v1 +12v2
Test 1
Test 2
Test 3
Test 4
Test 5
Test 6

Finishing up with the scope readings taken during the 50°C tests, it's easy to see that the Liberty ECO did extremely well. Ripple on the +3.3v and 5v rails stayed below 12mV in tests 1-4 and only got a little out of control, hitting 30mV in Test 5 when one of the wonky cross loads caught it off-guard. Equally...no in fact MORE impressive was the +12v rails, which stayed at under 20mV ripple throughout the entire test making the Liberty ECO one of the best PSU's I've tested so far in this regard.

Now let's move on to the conclusion where I attempt to sum up the previous few pages into a series of score graphs and pretty award logos :)

Enermax Liberty ECO 500w ATX PSU Page: 5

Enermax Liberty EC 500wAs we continually stress to our forum members here at Overclock3D: "500w is more than enough power for almost all PC systems providing you pick a good PSU". Judging by the results we've seen today that's exactly what the Enermax Liberty ECO 500w is: a very good PSU.

During testing the Liberty ECO managed to hold some extremely tight voltages across all of its rails, with the +12v lines only dropping by 0.13v from idle to full load. Both the +3.3v and +5v rails also maintained good stability with a drop of 0.06v and 0.12v respectively. Only when applying a heavy crossload to the unit did things start to get a bit out of hand in Test 5 with the +12v rails shooting up to around 12.8v. However, as I've said many times before, this isn't a situation that you are likely to ever come across on a normal PC, so it's hard to give the Liberty ECO negative marks for this result alone.

Efficiency was also extremely reasonable with 84-85% being achieved under most loads. Sure there are PSU's out there capable of maintaining 88-90% efficiency, but at present these units are extremely expensive - and let's face it, it's not until you start sucking really large amounts of power from the wall socket that a 3% efficiency difference would actually be noticeable.

Finishing off with the scope results conducted while the PSU was roasting away in our 50°C oven, I think its fair to say that these were outstanding. Ripple on the +12v rails never exceeded 20mV even when at full load, and similarly the results from the +3.3v and +5.0v were also among the lowest I've ever seen. Amazing.

At time of writing the Liberty ECO is only available at a limited number of UK based retailers. Scan is one of these few and has the 500w model listed at £85.47. This in all fairness, is at the top end of the scale for what I'd expect to pay for a 500w unit especially considering respectable PSU's from manufacturers such as Seasonic, Silverstone and Cooler Master can be had for £65+.

The Good
- Excellent ripple results.
- Stable voltages, even under heavy load.
- Around 84-85% efficiency at most load levels.

The Mediocre
- Cable sleeving falls short of the cable length.
- Some dodgy voltage and ripple results in certain crossload situations.

The Bad
- 5 modular connectors on PSU, yet only 4 modular cables provided.
- Price quite high for a 500w unit.

Recommended Award

Thanks to Enermax for providing the Liberty EC for review. Discuss this review in our forums.