Our load tests utilize a couple of FAST ATE active load testers and a variety of other equipment such as an oscilloscope, power conditioner, temperature probe and a power consumption meter. You can read more about our standard testing approach here.
The tests performed are based around six conceivable setups that are out there and progressively load down the PSU up to the power supply's limits or 1000W, whichever comes first. Since our test equipment's limits are higher than that of the be quiet! Power Zone 850W power supply, we can test it to the maximum.
The above tests represent typical loads that we have measured from various systems and are meant to give a rough idea of where your computer might fall in line with our tests. Please keep in mind that each system is different and actual loads can vary greatly even with similar hardware.
Let's start by taking a look at the voltages to see how well this unit did during testing. Starting with the 12V rail, we see 2% regulation from start to finish with a total drop of .18V. The 5V rail managed to stay within 3% of specification with a total drop of .11V from start to finish. Moving towards the 3.3V rail, we see that regulation was within 2% of specification with a total voltage drop of .07V.
DC Output quality for the be quiet! Power Zone 850W was good and well within specifications. During Test 1, we saw 15mV of noise on our scope. When we increased the loads in Test 3, the ripple climbed to 27mV at a little over half load. During Test 5 under a load of 850W, the oscilloscope showed a maximum of 43mV on noise on the 12V rail.
The be quiet! Power Zone 850W is rated for 80 PLUS Bronze efficiency. This means that the power supply must perform at 82%/85%/82% efficiency at 20%/50%/100% loads respectively. As you can see, the Power Zone 850W passed on our bench, and wasn't close to failing at any point.
As with everything we have seen to date from be quiet!, we are pleased overall with what the Power Zone 850W power supply has to offer. As we looked over the product, we really didn't find anything to complain about, other than the FDD connector chained at the end of an already long cable. We also came across a bunch of Teapo capacitors, some of which did not meet the claim of 105C rated caps as stated on the back of the box. Although it doesn't say that ALL of the capacitors are rated for 105C, it feels implied.
When we talk about performance, we are happy to say that the Power Zone performs just as you would think it should for a unit that is in the middle of their low-end and high-end units. Voltage regulation was within 2% for the 12V and 3.3V rails and it dipped into 3% for the 5V rail. I find it somewhat unrealistic to expect more than this out of a mid-range unit. DC output quality was right where I expected it to be after seeing the full set of Teapo caps on inside of the unit. We've seen better numbers from be quiet! in the past, but they have all been units with Japanese capacitors. The Taiwanese caps have come a long way, but they are still subpar to what you get from the Japanese.
The real downer on this power supply is the price. At an MSRP of ~$160, it places is self in the price range of something like the Corsair RM850, which performs just as well, but has better efficiency and is able to be monitored via Corsair's software.
The sale at NCIX makes it a no brainer if you can catch it for $100, but otherwise, it needs a solid $20 price drop. Until that happens, I have to say the be quiet! Power Zone 850W is a good unit, but definitely overpriced.