NZXT C650 650W Report (Page 4 of 4)

Page 4 -Minor Tests and Conclusion

Power supplies are interesting products -- because often, reviews of products in this category are conducted and tested in methods that make it difficult to distinguish one power supply from another. Many aspects must be taken into consideration -- of which certain criteria consists of efficiency, noise, power ripples, and of course the ability to pull out the rated specifications. Because many cannot afford such equipment to obtain results regarding those aspects, articles covering power supplies often come out with less than adequate and acceptable information. As this is a product report -- not a review -- what we are doing is a close examination of the power supply and the internal hardware and build. But what we can do for you is do some minor testing with the results we can present to you with, and let other review sites with professional equipment show you the actual test results. We are not going to try to create useless test results by installing the power supply into the latest gaming rig and try to take readings from that, as this is not even remotely the correct way to test power supply units. We understand that many websites do that as a means of load testing, but the results, even if you use an oscilloscope and multimeter at each output location, it is not sufficient, nor does it accurately reflect the performance of the power supply.


Using our power supply tester that exerts minimal load on the power supply, initial consumption was 11W as measured by our wall meter, indicating the basic load-free power consumption of the power supply is excellent. Independent reviews from our affiliates with professional load testing equipment showed the NZXT C650 650W was able to deliver excellent energy efficiency, voltage regulation, as well as the ripple performance for all rails. Keep in mind that this is an 80 Plus Gold certified power supply unit.

Voltages with minimal load are generally accurate, which is a basic requirement of power supplies out of the box. In this situation, all are well within 4%. The PG (Power Good) delay seems to be well within its rated range and general power supply standard at 360ms.

Active power correction is important to correct AC load line loss. In AC power, there are three components to it since there is a phase difference between current and voltage. This makes up the power triangle, which consists of the following: Average usable power (P, measured in watts), reactive power (Q, denoted as VA-R), and total power (S, written as VA). While these are all power measurements, they cannot be considered as one thing. What we want is the average usable power, with as little wasted reactive power as possible. The total power provided over the AC line is the magnitude of the two combined (sqrt(P^2+Q^2)). Power factor can now be easily calculated as P/S. The ideal value is 1.00, and this is where APFC comes in. The NZXT C650 650W has APFC, which means the power factor will approach 0.99 with a nominal load.

The cooling fan in the NZXT C650 650W power supply unit can run in active mode or semi-passive mode, depending on user preference. Using the APH Networks noise scale that defines 0 is silent and 10 is the loudest, I would rate this power supply unit as 2.0/10 acoustically under normal loads in active mode. In Zero RPM fan mode, I would rate it at 0.0/10, since the fan is off. The Zero RPM fan mode can only be enabled at low-load conditions according to the product's retail box. The exact definition of low load is not defined, but generally speaking, if the load or temperature is above some threshold, it will come on automatically.

NZXT provided this product to APH Networks for the purpose of evaluation.

The NZXT C650 650W is overall a compact, well-designed, and well-built fully modular power supply unit with a semi-passive fan mode. The internal design is appropriate for an ATX unit, and all the internal components are of good quality. The use of 100% Japanese-made capacitors boosts up my confidence in the product. The ten-year warranty is equally impressive considering it is not the most expensive product from the company. According to our affiliates, this product performs generally very well. The retail price of this review unit is $110 USD at press time. I think the price is fair, considering the good quality components and an 80 Plus Gold certification.


Page Index
1. Introduction, Packaging, Specifications
2. Physical Look - Outside
3. Physical Look - Inside
4. Minor Tests and Conclusion