Introduction

We would like to thank Zalman for supplying the review sample.

Zalman was founded in 1999 and from the start they embraced the concept of noiseless computing. Initially Zalman offered only silent cooling solutions but their huge success in this field and the rapid growth of the company latter brought their enrollment into 2D/3D convertible LCD monitors, heatpipe cooled PSUs, notebook coolers and various sound and gaming products.

The latest addition in Zalman’s PSU products are the ZM1000-HP Plus and the ZM850-HP Plus, two PSUs that like their predecessors, ZM1000-HP and ZM850-HP, utilize a dual heat-pipe cooling system to effectively cool the internal components and dramatically decrease the cooling fan’s RPMs and thus reduce noise levels.

In this review we will test the ZM850-HP Plus which utilizes a semi-modular design, it has 80PLUS Silver efficiency and can power up to three graphics cards with the six PCIe connectors that is equipped. Finally, one of the most notable characteristics of this PSU besides the heatpipes cooling is its huge length, which reaches 210mm!

Specifications

The maximum operating temperature is only 40°C while the ATX specification states that any compliant PSU should be able to deliver its full power at 50°C. Nevertheless in our hotbox we will crank up the temperature up to 50°C. Also we noticed that the warranty is only three years while the competition often gives five or even seven years to its hi-end PSUs. We think that Zalman should revise and increase the warranty period. Finally besides OPP (Over Power Protection) all other protections are present in this PSU.


The PSU features four +12V rails. As you can see the +12V rails are not equally rated since 12V3 and 12V4 have a load output rating of 35A and 28A respectively while 12V1 and 12V2 are rated at 25A each. Finally the 5VSB rail is fairly strong with 3.5A maximum output.

Cables & Connectors, Power Distribution

Cable length is satisfactory and the distance between the connectors is close to the recommended by ATX: 150mm. The lack of a second EPS connector caught us by surprise. Regarding wire size, the peripheral and SATA connectors use 18 AWG wires while ATX, EPS and PCIe connectors use thicker 16 AWG wires for decreased resistance. Finally we wonder why not all PCIe connectors are 6+2 pin. The most logical explanation is that since the PSU has only 850W capacity the manufacturer thought that six 6+2 pin PCIe connectors (each rated to 150W) would be too much.


Power distribution is not optimal since 4 pins of the EPS connector (ATX12V) are fed from the same rail that powers two PCIe connectors. It would be much better if 12V2 solely powered the EPS connector. Also strangely enough while the 12V3 rail is rated to the highest current, it powers less connectors compared to 12V1 and 12V4. It seems that Zalman or the OEM of this PSU designed the rails distribution with no specific plan in mind.