Review Index:

Zalman ZM1000-HP 1,000W Power Supply Review

Manufacturer: Zalman

Introduction and Features

The ZM1000-HP power supply is the latest and largest addition to Zalman’s line of PC switching power supplies.  It features a combination of fixed and modular cables, support for dual CPUs and multiple high-end graphic cards, and can deliver up to 1,000 watts of continuous DC output.  The ZM1000-HP uses two heat pipes to augment the internal cooling system for increased reliability and to reduce noise.  While not the first PSU manufacturer to take this approach, Zalman certainly has a strong history of effectively using heat pipes in many of their CNPS (Computer Noise Prevention System) enabled products.

(Courtesy of Zalman)

Zalman has a well earned reputation in the PC industry for delivering high-quality components that are designed to reduce noise.  In addition to PC power supplies, Zalman also offers desktop and HTPC enclosures, air and water-cooling solutions, along with numerous noise fighting accessories for the PC enthusiast.

Zalman ZM1000-HP PSU Key Features:

•    1,000 watt continuous power output

•    Heat pipe technology used to enhance cooling

•    Quiet 140mm cooling fan maximizes airflow

•    ATX12V v2.2 and EPS12V support

•    Six +12V outputs (up to 80A/960W combined)

•    Four PCI-E connectors (NVIDIA Quad SLI and ATI CrossFire support))

•    High efficiency (up to 86%) and 80 PLUS Certified

•    Combination of Fixed and Modular cables (fully sleeved)

•    16 AWG (heavy gauge) wire used to minimize voltage drop

•    EZ grip connectors with gold plated terminals

•    Noise Filter Switch for +5VSB

•    Active PFC with Universal AC line input

•    3-Year warranty 

Heat Pipe Technology

The Zalman ZM1000-HP power supply uses two copper heat pipes to transport heat from the main heatsinks over to arrays of aluminum fins that are cooled by air exhausting out the back of the power supply.  Zalman isn’t the first company to use heat pipes to help cool a power supply.  Both Silverstone and Thermaltake used heatpipes in their fan-less PSU’s several years ago. 

A heat pipe is a highly efficient conductor of heat and using one in this manner greatly increases the effective surface area of the internal heatsink.  A properly constructed heat pipe has a very low thermal resistance, which is roughly independent of its length (unlike ordinary metal rods whose thermal resistance increases with length).  Heat pipes are commonly used to transport heat from one location to another.


Heat pipes work on the principle of evaporation and condensation.  A working fluid (frequently distilled water) evaporates inside one end of the heat pipe (the hot-end) absorbing heat in the process.  A partial vacuum inside the heat pipe allows the water to evaporate at low temperatures.  Once formed, the water vapor diffuses from an area of high vapor pressure (where it is being generated) to the other end of the tube where the vapor pressure is lower.

The vaporized fluid then condenses back to liquid (cold-end) and the heat is dissipated into the air from the metal cooling fins.  The working fluid returns to the hot end via capillary action thru an internal wicking structure (sintered metal coating, fine wire mesh, or grooves) so the heat pipe does not have to rely on gravity to recycle the working fluid.  The key to a heat pipe’s high efficiency is the working fluid’s latent heat of vaporization.

Packaging and Parts

The Zalman ZM1000-HP power supply arrived securely packed inside a retail box that highlights the power supplies features and specifications.  In addition to the power supply the package includes a power cord, mounting screws, ZM-DC1 fan adapter, a printed User’s Manual, and eight modular cables.

Establishing an accurate load is critical to testing and evaluating a PC power supply.  PCPerspective’s power supply test bench can place a precise 2,000 watt DC load on the PSU under test.  Each power supply is tested under controlled, real-world conditions up to its maximum rated load (at 40ºC), using both 115 VAC and 240 VAC line voltage.  Our current suite of tests includes:

•    DC Load Regulation

•    DC Line Regulation

•    DC Cross-load (unbalanced load)

•    AC Ripple and Noise

•    Power Factor

•    Efficiency

•    Differential Temperature

•    Noise

The Zalman ZM1000-HP power supply was evaluated on both features and performance.  A full range of equipment was used to test the power supply under controlled load conditions. 

•    (2) CSI3710A Programmable DC load (+3.3V and +5V outputs)

•    (4) CSI3711A Programmable DC load (+12V1, +12V2, +12V3, and +12V4)

•    FLUKE 87-III True RMS digital multimeter (Accuracy ±0.05%)

•    Extech 380803 Power Analyzer (Accuracy ±0.5% of full scale)

•    Hitachi V-650F 60 MHz dual trace oscilloscope (Accuracy ±3%)

•    Powerstat Variable Autotransformer, 1.4 KVA, 0-140 VAC

•    FLUKE  52-II digital thermometer (Accuracy ±0.3ºC/0.5ºF)

•    Extech Model 407738 digital sound level meter (Accuracy ±1.5 dB)

•    Custom Lian Li PC60 enclosure to simulate real-world operating conditions