XigmaTek NRP-PC702 Power Supply Review

1. Introduction2. The Packaging/Bundle3. XigmaTek NRP-PC7024. XigmaTek NRP-PC702 (Inside)5. Testing Methodology and Results6. Closing Thoughts7. View All Pages

Earlier this year Xigmatek released a couple of power supplies which didn't receive much coverage, but we really liked the whole ‘eco friendly' approach they were focusing on, heck they even shipped the unit in a box made from recycled materials.

They have four supplies in this range, The PC402, PC502, PC602 and PC702; with the first number in the product name signifying the power output. The PC702 we are looking at today is therefore a 700W model, the highest in this particular range. These models are marketed at the everyday enthusiast with a high value element to ensure they are easily affordable – The PC702 for instance is only £70 in the UK right now. We need to balance out our test units as we have, to this point, focused primarily on expensive, high end power supplies.

The Xigmatek NRP-PC702 Power Supply is 80 PLUS Bronze certified which means it has to have an efficiency rating of 85 percent or greater when under 50 percent load.

A full list of specifications is available here

Product Overview

• Real and stable 700W output
• High efficiency over 85%
• Compliant with ATX12V Ver.2.3
• DC quality with low ripple noise
• 0.99 Active PFC rate
• Japanese 105°C Main Capacitor
• 140mm silent cooling fan
• Smart thermal fan control
• All DC cables with mesh sleeve
• PCIe graphic card connector support , supports high-end graphic card with PCIe 6/8pin connector.

If you are an eco friendly kind of person then this box is really going to appeal to you, it has been made completely from recycled materials and has a really great feel to it. The text is hard to read in places mind you, but we like the appearance, its very striking.

Inside, the unit is protected by heavy duty foam on either side and there is a box on the rear side with the cabling on the right. As this isn't a modular supply all the cables are wrapped with one very large felt cable tie.

The package contains a manual, warranty information, some cable ties and a power cable.

The power supply is protected inside a felt wrap which offers protection against scuffing during shipping. This is reusable which gives a little extra substance to the eco friendly approach from Xigmatek.

The power supply itself is a plain looking product finished in a grey casing which should work well in a variety of cases. We had secretly hoped it would be finished in green to match the ‘environmental' theme, but this would probably look rather ugly.

The 140mm fan takes pride of place on the top of the Xigmatek PC702 and if configured correctly should mean that this PSU is a relatively quiet unit.

There isn't much happening with the design, its plain grey from all angles, with only a sticker on the side showing the output specifications. The unit can deliver 54A on the 12V line (648W).

The cabling included is as follows:

• 1x 24 pin ATX connector
• 1x 4/4 12V CPU power connector
• 2x 6 pin 12V PCIe connectors
• 2x 6+2 pin 12V PCIe connectors
• 8x Sata Connectors
• 1x Floppy Connector
• 7x Molex Connectors

This is pretty much as we would expect from a 700W modern day PSU and there is enough connectivity to satisfy the majority of the enthusiast audience.

The fan is made by Young Lin Tech (DFS132512H) – a similar model used in the recent Cooler Master Silent Pro M 600W review. As the lighting shows above the fans are partially transparent which gives it a nice appearance, it is limited to 1,700 rpm and is thermally controlled.

Internally the unit is clean and rather spartan looking and this is following a HEC design who are the OEM behind this particular implementation. The heatsinks look rather small however and we hope this won't affect the cooling performance later in the review.

The primary capacitor is a high quality Nippon Chemi Con industrial grade product which is rated to 105c, 400v/470uf. The soldering on the PCB is of a very high quality with no apparent issues on the engineering side.

The transient filtering stage is composed of two Y capacitors and two X capacitors and the design is yet again simple and clean.

The secondary stage capacitors are high quality, industrial rated Teapo products. The cabling is fully sleeved into the unit which should stop any possible wire fraying on a long term basis.

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
• SkyTronic DSL 2 Digital Sound Level Meter (6-130dBa)
• Digital oscilloscope (20M S/s with 12 Bit ADC)
• Variable Autotransformer, 1.4 KVA

We will combine both 12V rails into one for testing today.

DC Output Load Regulation
Combined DC Load	+3.3V		+5V		+12V		+5VSB		-12V
	A	V	A	V	A	V	A	V	A	V
174W	3.25	3.36	3.25	5.00	11.50	12.11	0.75	5.18	0.12	-12.09
352W	7.50	3.33	7.50	4.99	23.00	12.10	1.50	5.10	0.25	-12.10
525W	11.25	3.33	11.25	4.98	34.50	12.08	2.25	5.05	0.37	-12.10
700W	15.00	3.31	15.00	4.97	46.50	12.06	3.0	4.99	0.50	-12.11

The Xigmatek power supply is able to handle our load tests with relative ease even when delivering the maximum rated power output of 700W.

XigmaTek NRP-PC702	Maximum Load
	787.4W

We managed to push the unit to 787.4W before it would shut down, gracefully. Overcircuit protection works fine and we experienced no issues.

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
590W	1.0	3.34	1.0	5.05	48.0	12.05	0.2	-11.99	0.5	5.02
190W	18.1	3.28	20.0	4.98	2.0	11.96	0.2	-12.05	0.5	4.99

The Xigmatek unit delivers stable results under our intensive cross load testing with not much fluctuation throughout.

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 Xigmatek unit complied with the ATX standard.

AC Ripple (mV p-p)
DC Load	+3.3V	+5V	+12V	5VSB
174W	10	10	25	5
352W	10	10	30	10
525W	15	10	35	10
700W	15	15	40	10

Ripple results are fantastic throughout and well within the parameters set down in the ATX 12V Ver 2.2 standard. The 12V line registered between 35 and 40 mv as we reached the upper levels of performance. The 3.3V and 5V lines were rock solid.

Efficiency (%)
174W	86.3
352W	88.2
525W	87.3
700W	85.3

The NRP-PC702 exceeds Bronze certification, peaking at 88.2 percent efficiency around 50% load. An excellent set of results for the Xigmatek unit.

Noise (dBA)
174W	19.2
352W	24.2
525W	27.8
700W	35.3

The supply remains quiet until around 75% load when it starts to become audible. At full load the PC702 registers around 35 dBA which is clearly noticeable.

Temperature (c)
	Intake	Exhaust
174W	35	37
352W	37	42
525W	39	48
700W	43	56

As we get nearer to full load the exhaust temperatures increase which is clearly not helped by the rather small heatsinks inside the supply. We feel Xigmatek could have made these 33% larger to really help with cooling efficiency, there is a lot of space in this chassis going to waste.

Maximum load	Efficiency
787.4W	82.8

Pushing the PSU above its rated limits generates an efficiency level of around 82.8%. This is not a viable ‘real world’ situation, but its interesting nonetheless.

The Xigmatek NRP PC702 is an impressive power supply which delivers great all round performance, it excels at this specific price point. The build quality is good, and while the unit looks a little boring it will fit into a variety of systems without standing out like a sore thumb. We would have liked to see Xigmatek be a little more creative with the finish, especially considering the eco friendly ‘heal the world' angle they have approached this from.

Technically there is not a lot to fault, the power supply features all the major protection circuits and delivers efficiency ratings above the 80 Plus Bronze certification rating, something we always like to see. Internally, the build quality is excellent and the industrial components chosen are of a high standard throughout. The voltage regulation circuit is also worth a mention as it held up to our severe stress testing.

The only aspect of the design we would change would be to replace the heatsinks with something more substantial. The fan generates a reasonable amount of noise under load as it tries to deal with the rising heat and we hope to see a revision two of this unit with beefier heatsinks … it shouldn't be that difficult because you could almost park a bus in the unused space inside the chassis. A modular version of the PSU would be a nice option also.

KitGuru says: Everything considered, the power supply is a great purchase as it has no real weaknesses and is technically a very strong design. The cherry on the cake however is the fact you can pick this up for £69.98 inc vat. It really is hard to fault for such a great price.

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