Enermax NAXN 850W Power Supply Review

1. Introduction2. Enermax NAXN 850W Power Supply (Bundle and Cables)3. Enermax NAXN 850W Power Supply (Exterior)4. Enermax NAXN 850W Power Supply (Interior)5. Testing Methodology and Results6. Closing Thoughts7. View All Pages

Enermax have earned a solid reputation as one of the leading power supply manufacturers and they have recently launched a new series of units aimed at the entry level marketplace. These power supplies are rated between 350w and 850w and have been designed for a wide range of applications such as basic office PC use and high end gaming systems.

Today we are looking at the high end NAXN 850W model which has been created with high demand gamers firmly in mind. It is a 80 Plus Bronze Certified power supply with a modular design for clean cable management, and is supplied with a silent 120mm fan. It is also ErP Lot 6 ready.

• 80 PLUS® Bronze efficiency
  Up to 88% efficiency at 230V and 20-100% load. 80 PLUS® Bronze certified.
• Future ready and flexible
  All-round modular cable management. 10/12P sockets for possible connector changes of upcoming high-performance CPU and graphics card generations.
• DXXI ready!
  Full support of most current DX11 graphics cards due to min. four 6+2P (8P) connectors.
• Full graphics power
  Supports SLI systems and CrossFireX systems.
• HeatGuard
  Keeping PSU fan running for 30-60 seconds after shut down to dissipate the remaining system heat and prolonging system lifetime.
• Non-Stop @ 40°C
  Non-stop industrial class performance at 40°C/104°F ambient.
• ENERGY STAR 5.0 ready!
  Support computer system to meet ENERGY STAR 5.0 standard.

The NAXN 850W power supply is delivered in a rather bland box which looks a little like an 80's grunge metal band's album cover.

Inside there is literature on the product, a power cable, cable tidies and a handy storage pouch for the modular cables.

The modular cables are high quality and sleeved, several of them are fixed into the body of the chassis. The inclusion of 4x 6+2 pin PCIE connectors mean that high powered CrossfireX and SLI systems are fully supported.

The Enermax NAXN power supply is nicely finished with a scratch resistant paint job.

The 120mm fan is clear, and is housed under a gold grill with the Enermax logo in the middle. The rear of the PSU is fully vented to allow for good airflow circulation. There is a power button and connector to the side. Enermax state that the air intake system is patented with ‘optimal aerodynamic design' to reduce noise caused by airflow.

The modular connectors are colour coded to help with installation. All the peripheral devices connect via the black headers, and the graphics cards and CPU are hooked into the red section to the right. It is basically foolproof and reminded us of the recent ADATA construction layout.

Enermax NAXN 850W
DC Output	+3.3V	+5V	+12V1	+12V2	+12V3	+12V4	-12V	+5Vsb
	28A	30A	20A	20A	30A	30A	0.8A	3A
	180W		750W (62.5A)				9.6W	15W
Total Power	850W

The power supply can deliver a total of 62.5A on the +12V output which is healthy.

Enermax are using a Globe Fan, model number RL4Z B1352512H. This is a ball bearing fan with a maximum rated rotation speed of 1,500 rpm. We have seen this fan used in other power supplies such as those by OCZ. It is a common choice within Sirtec manufactured supplies. The fan runs for between 30 to 60 seconds after the power supply has been shut down to help dissipate the remaining system heat. This feature is not implemented on the 350W/450W and 550W models.

The power supply incorporates several rows of large heatsinks which will help ensure optimal running temperatures.

All models in the NAXN range are based on an improved 5V standby circuit to reduce the energy loss by about 20 percent and to support ErP Lot 6. We are pleased to see high quality 105c Rubycon capacitors used in the design. The power supply supports multiple protection across OVP, UVP, OPP, SCP and SIP.

The cables are fully sleeved inside the chassis with cable ties, there is also a rubber protective strip across this section to ensure long term safety and protection against fraying.

Additional technical assistance: Peter McFarland and Jeremy Price.

Correctly testing power supplies is a complex procedure and KitGuru have configured a test bench which can deliver up to a 2,000 watt DC load. Due to public requests we have changed our temperature settings recently – previously we rated with ambient temperatures at 25C, we have increased ambient temperatures by 10c (to 35c) in our environment to greater reflect warmer internal chassis conditions.

We use combinations of the following hardware:
• SunMoon SM-268
• CSI3710A Programmable DC load (+3.3V and +5V outputs)
• CSI3711A Programmable DC load (+12V1, +12V2, +12V3, and +12V4)
• Extech Power Analyzer
• Extech MultiMaster MM570 digital multimeter
• Extech digital sound level meter
• Digital oscilloscope (20M S/s with 12 Bit ADC)
• Variable Autotransformer, 1.4 KVA

DC Output Load Regulation
Combined DC Load	+3.3V		+5V		+12V		+5VSB		-12V
	A	V	A	V	A	V	A	V	A	V
100W	1.56	3.37	1.77	5.04	6.62	12.15	0.50	5.05	0.20	-12.15
225W	3.72	3.35	3.83	5.03	15.52	12.08	1.00	5.04	0.20	-12.13
450W	7.52	3.33	8.34	5.02	30.66	12.05	1.50	5.03	0.30	-12.13
675W	11.32	3.30	12.37	5.01	47.44	11.95	2.00	4.98	0.50	-12.12
850W	1.41	3.27	1.15	5.00	63.34	11.86	0.50	4.95	0.20	-12.12

The NAXN 850W delivered excellent load regulation on all output channels across a wide range of loads. These are good results and the +3.3V and 5V rails remained firmly within +/-2% of the nominal voltage instead of the recommended +/-5%.

Enermax NAXN 850W	Maximum Load
	915W

We managed to get the PSU to hit 915W before it would shut down. delivering around 65W more than the rated specifications. It would run at 900W for quite a while.

Next we want to try Cross Loading. This basically means loads which are not balanced. If a PC for instance needs 500W on the +12V outputs but something like 30W via the combined 3.3V and +5V outputs then the voltage regulation can fluctuate badly.

Cross Load Testing	+3.3V		+5V		+12V		-12V		+5VSB
	A	V	A	V	A	V	A	V	A	V
760W	1.0	3.27	1.0	5.02	60.0	11.77	0.2	-12.04	0.50	5.00
165W	15.0	3.28	18.0	4.97	2.0	12.03	0.2	-12.02	0.50	4.97

Again, these are very good results with fluctuation held safely within the rated parameters, even when loading the unit with 60A on the 12V. The +12V rail dipped a little, but it is still safe enough.

We then used an oscilloscope to measure AC ripple and noise present on the DC outputs. We set the oscilloscope time base to check for AC ripple at both high and low ends of the spectrum.

ATX12V V2.2 specification for DC output ripple and noise is defined in the ATX 12V power supply design guide.

ATX12V Ver 2.2 Noise/Ripple Tolerance
Output	Ripple (mV p-p)
+3.3V	50
+5V	50
+12V1	120
+12V2	120
-12V	120
+5VSB	50

Obviously when measuring AC noise and ripple on the DC outputs the cleaner (less recorded) means we have a better end result. We measured this AC signal amplitude to see how closely the Enermax unit complied with the ATX standard.

AC Ripple (mV p-p)
DC Load	+3.3V	+5V	+12V	5VSB
100W	5	10	15	10
225W	10	15	15	15
450W	10	15	20	15
675W	15	15	30	15
850W	20	15	40	15

Ripple results are very impressive, across the board. The 12V rail registered around 40 mV with our equipment, which is well within the Tolerance guidelines.

Efficiency (%)
100W	84.57
225W	85.63
450W	87.86
675W	86.59
850W	85.23

For a 80 Plus Bronze specified unit, these results are very strong, showing a maximum efficiency rating, just shy of 88%. At maximum load this drops to around 86%, which is again, a great result.

We take the issue of noise very seriously at KitGuru and this is why we have built a special home brew system as a reference point when we test noise levels of various components. Why do this? Well this means we can eliminate secondary noise pollution in the test room and concentrate on components we are testing. It also brings us slightly closer to industry standards, such as DIN 45635.

Today to test the Corsair Power Supply we have taken it into our acoustics room environment and have set our Digital Sound Level Noise Decibel Meter Style 2 one meter away from the unit. We have no other fans running so we can effectively measure just the noise from the unit itself.

As this can be a little confusing for people, here are various dBa ratings in with real world situations to help describe the various levels.

KitGuru noise guide
10dBA – Normal Breathing/Rustling Leaves
20-25dBA – Whisper
30dBA – High Quality Computer fan
40dBA – A Bubbling Brook, or a Refridgerator
50dBA – Normal Conversation
60dBA – Laughter
70dBA – Vacuum Cleaner or Hairdryer
80dBA – City Traffic or a Garbage Disposal
90dBA – Motorcycle or Lawnmower
100dBA – MP3 Player at maximum output
110dBA – Orchestra
120dBA – Front row rock concert/Jet Engine
130dBA – Threshold of Pain
140dBA – Military Jet takeoff/Gunshot (close range)
160dBA – Instant Perforation of eardrum

Noise (dBA)
100W	27.7
225W	28.8
450W	31.3
675W	33.8
850W	36.3

The power supply is quiet at moderate load and only becomes audible in the upper 30% of the power delivery, rising to around 36 dBa at full load.

Temperature (c)
	Intake	Exhaust
100W	36	38
225W	37	40
450W	39	45
675W	43	49
850W	45	54

Exhaust temperatures are good in the lower end of the spectrum, rising to a 9c above ambient result at full load. The 120mm is quiet and spins under 1,300 rpm at all times.

Maximum load	Efficiency
915W	83.12%

For those interested, we measured efficiency when stressing the unit to breaking point. Over 83% at 915W … hardly practical, but interesting regardless.

The Enermax NAXN 850W is a well rounded power supply which offers high power output at a very respectable price point. Technically, the design is good, you are given solid 80 Plus Bronze efficiency with a very stable power delivery which held well across many days of intensive stress testing.

The NAXN 850W scores high with load regulation, ripple and efficiency and it doesn't generate a lot of noise either, which will appeal to gamers who are trying to ditch an older, less efficient power supply.

On a design level – we like the appearance. Some of the Enermax power supplies can look a little gaudy at times, but the subdued paintwork and gold fan grill will look attractive within any system build. The modular cables are high quality and sleeved, with a fantastic and clearly coded modular layout on the chassis to ensure that even inexperienced system builders don't experience any build problems.

When it comes to purchasing an 80 Plus Bronze power supply the decision can often be based around the retail price.

Right now in the UK the Enermax supply costs £120 inc vat, which compares reasonably well against the competition. That said, there are other high quality modular supplies such as the HX 850W from Corsair which cost only £5 more and offers 80 Plus Silver certification. Corsair also have a longer 7 year warranty system, Enermax is 3 years.

In real world terms, this supply has been powering an overclocked Core i7 980X system with two GTX580's in SLI for the last week. The system has been rock solid since we started using it and while the power supply could get warm under extended load we experienced no instability or random crashes, which can happen with a lesser unit design.

The NAXN 850W earns our WORTH BUYING award, it isn't a clear market leader in such a competitive sector, but it is certainly worth shortlisting for your next upgrade.

Pros:

• Price point is competitive
• technically, its a solid design
• modular layout is excellent
• nice appearance
• great build quality

Cons:

• Facing some competition at £120 from other leading units

KitGuru says: A quality product from Enermax.

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