Zalman ZM850-HP Plus 850 W 2

Zalman ZM850-HP Plus 850 W Review

Packaging, Contents & Exterior »


Zalman ZM850-HP Plus Features & Specs
Max. DC Output850W
Efficiency80Plus Silver
Operating temperature10°C - 40°C
ProtectionsOver Voltage Protection
Under Voltage Protection
Over Current Protection
Over Temperature Protection
Short Circuit Protection
Cooling140 mm Double Ball Bearing Fan
Dimensions150 mm (W) x 86 mm (H) x 210 mm (D)
Weight2.4 kg
ComplianceATX12V v2.3, EPS12V
Warranty3 years
Price at time of review199.99$

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.

Zalman ZM850-HP Plus Power Specs
Max. Power20A25A25A25A35A28A3.5A0.5A
Total Max. Power850W

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

Native Cables
ATX connector (530 mm)20+4 pin
4+4 pin EPS12V (540 mm)1
6+2 pin PCIe (500 mm) / 6 pin PCIe (+ 140mm)1 / 1
Modular Cables
6+2 pin PCIe (510 mm) / 6 pin PCIe (+ 140mm)2 / 2
SATA (500 mm+140 mm+140 mm)9
4 pin Molex (500 mm+140 mm) / FDD (+140 mm)2 / 1
4 pin Molex (500 mm+140 mm+140)6

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
12V1EPS, PCIe3, PCIe4, Peripheral
12V3PCIe1, PCIe2
12V4PCIe5, PCIe6, SATA

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.
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