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 lower than that of the Zalman ZM1250 Platinum 1250W power supply, we can only test it to 1000W.
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 12V1 rail, we see 2% regulation from start to finish with a total drop of .17V. 12V2 was within 2% regulation from start to finish and also had a total drop of .17V. The 5V rail managed to stay within 2% of specification as well with a total drop of .07V from start to finish. Moving towards the 3.3V rail, we see that regulation was once again within 2% of specification with a total voltage drop of .07V.
DC Output quality for the ZM1250 Platinum 1250W was great and well within specification. During Test 1, we saw 16mV of noise on our scope. When we increased the loads in Test 3, the ripple climbed to 23mV at a little under half load. During Test 6 under a load of 1000W, the oscilloscope showed a maximum of 39mv on noise on the 12Vrail.
The Zalman ZM1250 Platinum 1250W power supply is rated for 80 PLUS Platinum efficiency. This means that the power supply must perform at 90%/92%/89% efficiency at 20%/50%/100% loads respectively. As you can see, the ZM1250 Platinum passed on our bench, and wasn't close to failing at any point.
The Zalman ZM1250 Platinum 1250W power supply is a quality unit inside and out, there is no doubt about it. Most couldn't ask for more out of a power supply and the ZM1250 Platinum delivers where it matters most as well. The voltage regulation, DC output quality and efficiency are all top notch and make it a solid contender with those such as Antec, Cooler Master, PC Power & Cooling, and many others.
Aside from a little bit of spilled adhesive on the outside of the unit, we couldn't find anything to complain about with the power supply itself. The five year warranty is nice, but we all know that Zalman could easily warrant the unit for seven years instead and it wouldn't affect them any.
The big downfall of the ZM1250 Platinum comes when you consider the price. At $300, it is a very expensive unit and one of the most expensive sub-1300W units on the market. With current rebates, it is only $10 less than Corsair AX1200i.
It is a shame to see such a price tag ruin a good unit, but that is what it comes down to with the ZM1250 Platinum. It has everything needed to make it a great unit with the exception of value. Once it comes down in price a little bit it will be a much stronger contender in the power supply market.