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 equal to that of the Zalman ZM1000-HP Plus, we can test it to the maximum.
Zalman's ZM1000-HP Plus performs excellent throughout all of our tests. All of the rails show minimal changes in voltages and never even come close to falling outside of the ATX specifications. Efficiency was also spot on for the 80Plus Silver rating on the power supply. Zalman has also managed to keep the ripple down on the 12V rail. Even under full load, the ZM1000-HP Plus only measured 28mV peak to peak.
The dual heat pipe design combined with the 140mm fan kept the Zalman ZM1000-HP whisper quiet through all of the tests as well and could barely be heard. It wasn't until the power supply reached the third test that the fan even became audible which is approximately 56% load. The fan noise remained the same throughout the rest of the tests.
Zalman has produced a very solid power supply with the ZM1000-HP Plus. It performed very well in our load tests and one simply can't ask for a power supply to perform much better. Zalman's inclusion of dual heat pipes to cool the power supply coupled with a large 140mm fan to dissipate the heat and provide fresh air is fantastic. It keeps the power supply nearly silent even under load and makes it ideal for those seeking silent powerhouses.
Zalman could still do several things to improve the quality and value of the unit. The price is quite steep for a 1000W power supply. There are many others out there that offer nearly the same output performance wise for much less, but aren't quite as silent. Not utilizing a grommet as the wires come out of the power supply is something that I have only seen in a handful of power supplies over the last five years or more, and never in such a high end unit. The warranty on the ZM1000-HP is also a bit short, especially when looking at the offerings of other high end power supplies available.
After the great capacitor fiasco of the early 2000's, many people still remain highly reserved about any PC product that incorporates them and is one of the main reasons there has been such a large focus the past couple of years on pointing out the inclusion of Japanese capacitors. Zalman made sure to point out that the power supply used Japanese capacitors on the box, but didn't mention that it was only throughout part of the power supply. It would be nice to see 100% Japanese capacitors through the entire PSU.