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. Certain criteria consist 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, are not sufficient, nor does it accurately reflect the performance of the power supply.
Using our power supply tester which exerts minimal load on the power supply, the initial consumption was 9W as measured by our wall meter unit, indicating that the basic load-free power consumption of the power supply is very good. Independent sources with professional load testing equipment showed the be quiet! Power Zone 2 750W delivered very good efficiency for its class and good voltage regulation and ripple across all rails. This power supply unit has 80 Plus Platinum and Cybenetics ETA Platinum ratings.
Voltages with minimal load are accurate, which is a basic requirement of power supplies out of the box. The Power Good or PG delay is tested at 170ms. This power supply is ATX 3.1 compliant and officially supports Alternative Sleep Mode with 100 to 150ms PG specifications, so it looks like the PSU tester I used was not fast enough to pick up the true PG signal. The ATX design specifications state a PSU's PG is required to be between 100ms and 500ms, with 250ms maximum for Non-Alternative Sleep Mode and 150ms for Alternative Sleep Mode.
Active power correction is important to correct AC load line loss. In AC power, there are three components to it, as 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 they all have the same physical units, it is not the same thing as aforementioned. 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 then be easily calculated by P divided by S. The ideal value is 1.00, and this is where active PFC comes in. The be quiet! Power Zone 2 750W has active PFC, and the power factor will approach 0.99 with a nominal load.
The be quiet! Power Zone 2 750W is a silent to very quiet power supply, depending on the amount of power being drawn. Under idle level loads, or less than approximately 50%, the Power Zone 2 750W is inaudible because the fan is shut off completely. Under moderate loads above 50%, the power supply remains barely audible. Personally, I found the Pure Wings 3 PUW3-14025-HR fan to be excellent, living up to the name of the brand. While this is very subjective, I am quite a picky person on noise. On a scale from 0 to 10 where 0 is silent and 10 is the loudest, I would rate the be quiet! Power Zone 2 750W to be at 0.0/10 when the fan is off, because, well, the fan is off. Above that, I would peg it at 1.0/10 acoustically under moderate loads. The fan is basically out of the way even when the load increases, but as with all fans, it will become more audible as it spins faster. This PSU is rated at Cybenetics LAMBDA A++ for noise, which is the highest tier. If you are a silent PC enthusiast, the be quiet! Power Zone 2 750W is a very respectable choice thanks to the PSU's acoustics-optimized design and silent to ultra-quiet fan curve profile.
be quiet! provided this product to APH Networks for the purpose of evaluation.
The be quiet! Power Zone 2 750W is a mainstream performance PSU with Platinum-grade efficiency certifications while highly optimized for minimal noise. It can operate in semi-fanless mode up to about 50%, but even when the fan comes on, the acoustic optimized Pure Wings 3 and super quiet fan curve will satisfy the pickiest of users. Internally, it is built on a FSP platform with a good selection of components. Furthermore, it is ATX 3.1 and PCIe 5.1 compliant for all your latest hardware. According to others with professional load testing equipment, the be quiet! Power Zone 2 750W delivers good performance. You will not get Japanese brand capacitors, but the Taiwanese brand Elite capacitors are considered to be a great non-Japanese brand alternative. For about $150 at press time, the be quiet! Power Zone 2 750W fulfills its mission of being an ultra-quiet but relatively affordable power supply with the latest certifications and a 10-year warranty to keep you assured.
Page Index
1. Introduction, Packaging, Specifications
2. Physical Look - Outside
3. Physical Look - Inside
4. Minor Tests and Conclusion
