Zalman ZM500-HP

Zalman ZM500-HP


Zalman have always been at the forefront of silent computing with their CNPS mark; accreditation for the quietest components. Today I have one of their modular power supplies, the ZM500-HP, which features a heatpipe fed heatsink.

About Zalman

We are thankful to those of you who have purchased our Noise Prevention products and computers, as well as to all of you who are visiting our website. If we fully utilize computers’ many functions such as communications, office productivity, and multimedia, our life can become more comfortable and enriching. In order for this to be achieved, the computer must first become more user-friendly.

Despite the fact that computers have become commonplace at home and at workplaces for a long time, true user-friendliness of the computers is still a long shot. At Zalman Tech, we strive to make that goal a closer reality through extensive research and development of our products. We were the world’s first in reducing computer noise down to lower than 20dB, thus creating a more user-friendly computing environment. Now it is possible to use a computer without distracting noise and to form high fidelity audio system or home theatre system without ambient noise.

Zalman Tech will continue to make efforts at creating more enhanced levels of user-friendliness in computing; we believe that we have the ability and determination to achieve this goal. Your support and interest are greatly appreciated.


AC Input Range
Voltage 100VAC ~ 240VAC ±10% DC OUTPUT
Frequency 47Hz~63Hz Output V. Output Load
AC Input Current
115VAC 10A Imin Imax Ipeak
230VAC 5A +3.3V 0.8A 24A 140W 500W
PFC Type Active PFC +5V 0.5A 24A
Power Factor 99% Maximum +12V1 1A 25A 408W
Inrush Current
Limit (@ Cold start at 25°C)
115VAC 60A +12V2 1A 18A
230VAC 100A -12V 0.0A 0.5A 18.5W
Efficiency 81% Maximum @230VAC, Full&Typical load +5VSB 0.1A 2.5A 3.5A
DC Output
Output V. Regulation Range At Full
Protection Features
+3.3V ±5% +3.14V~+3.47V Over Voltage Protection(OVP)
+5V ±5% +4.75V~+5.25V Over Current Protection(OCP)
+12V1 ±5% +11.4V~+12.6V Short Circuit Protection(SCP)
+12V2 ±5% +11.4V~+12.6V Over Temperature Protection(OTP)
-12V ±10% -10.8V~-13V Under Voltage Protection(UVP)
+5VSB ±5% +4.75V~+5.25V Ambient Temperature
DC Output
& Noise
Output V. Specification At Full
Operation 0°C ~ +50°C
+3.3V 100mV Storage -20°C ~ +80°C
+5V 100mV Ambient Humidily
+12V1 200mV Operation 5%RH ~ 95%RH
+12V2 200mV Storage 5%RH ~ 95%RH
-12V 200mV Dimensions
+5VSB 100mV 150(L) X 165(W) X 86(H) mm

The ZM500-HP

Zalman ZM500-HP
Click to enlarge
Zalman ZM500-HP
Click to enlarge

The ZM500-HP is packaged in a nice looking cardboard box, and has a good weight to it. The front shows a shot of the power supply itself, and marketing comments, including heatpipe cooled and that its SLI compliant.

Zalman ZM500-HP
Click to enlarge
Zalman ZM500-HP
Click to enlarge

Once out the box, you find that it’s modular, which is a good sign as modular units keep the amount of cables snaking round your case to a minimum. As with most modular PSU’s, the ATX cable is hard wired as you will always need it. One of the PCI-e power connectors is also hard wired to the power supply. On the back of the ZM500-HP, you can see the labelled ports for the various supplied cables. All of these ports are gold plated to reduce resistance and hence improve efficiency and lifespan.

Zalman ZM500-HP
Click to enlarge

The box contains a short manual, molex/SATA cables, a couple of PCI-e cables, and a ZM-MC1 connector. The ZM-MC1 has two fan connectors stuck to a molex input connector. The fan connectors are white and black, with the white connector being 5v while the black is 12v. This allows you to slow down an existing fan to reduce noise. This little connector is apparently sent with all of their power supplies. Unfortunately, there aren’t any cabled managing cable ties, unless you count the Velcro strips that are used to keep the cables together for packing.

There is the usual 20+4 pin ATX connector to allow back compatibility with older motherboards, while keeping current motherboard owners happy. Also, the P4 connector (4 pin) is split, allowing you to combine it to become 8 pins to plug into an EPS slot on your motherboard which is slowly becoming the norm.

The power supply isn’t certified to be 80+ efficient but the manual and website proudly say that the power supply is 84% efficient during typical and full load. Unfortunately they tell you what typical load is, but 84% isn’t a bad figure.

Strangely, there is no kettle plug included which could really annoy someone who needs one. Imagine buying a whole new PC, then having to wait a couple of days for a simple kettle plug. Make sure you don’t get caught out with that one.

Zalman ZM500-HP
Click to enlarge

The most interesting part of the power supply is the heatpipe cooling. As everything else that has even a slight association with either PC or cooling has heatpipes, its hardly a surprise that Zalman have decided to include one in it’s PSU.

The heatpipes channel heat from the heart of the unit to the rear, which means that the air travel through the unit has twice as much surface area to pick up the heat produced from the transforms inside. This means that the 120mm fan can rotate slower and make less noise. The air exits the back of the PSU through a honeycombed side, and you can read why here.

All of the molex connectors have the simply, yet extremely useful quick-release tab, that when pushed forces the plug out of whatever device its in. This means that you don’t have to use so much force when changing hard disc etc.

Zalman ZM500-HP
Click to enlarge

In order to power your graphics cards, there are two 6 pin PCI-e connectors that enable SLI or a single power-hungry 8800. Amusingly, this power supply isn’t listed on nVidias site for SLI, only the 600W version of this power supply is. This is interesting as there is an SLI logo on the front of the box, this probably doesn’t mean certification, only that there are two PCI-e connectors.

There are two SATA cables with three connectors on, three molex connectors, two with one FDD connector and two molex, and the other with three molex’s, and one additional PCI-e cable. With all these connectors, you can power a maximum of thirteen drives and two graphics cards (or one 8800) without additional splitters.


As the power supply isn’t one of the most powerful we’ve had our hands on, we’ll be testing with the following:

Core 2 Duo E6600 @ 2.7ghz
Asus P5W DH Deluxe
OCZ Special Ops 2GB PC6400
eVGA 8800 Ultra

The 8800 Ultra seems a little excessive, but we are trying to push the power supply and give it a hard time. It should be noted that the power supply shouldn’t be able to power the Ultra, considering as the Ultra (according to its packaging) needs 35 amps on its 12v input lines. The Zalman provides 43 amps total across its two 12v rails. This leaves a meagre 8 amps (96 watts) for anything else in your sy
tem. The Ultra’s power supply requirements are naturally exaggerated to ensure it works correctly however.

The PC was stressed with StressPrime and had RTHDRIBL running full screen (1280×1024) with Asus Probe monitoring the rails for 30 minutes. Idle results were taken with the PC doing absolutely nothing for 30 minutes. The results consist of the upper and lower limits of the individual rails showing how much each rail varies by.

Zalman ZM500-HP

The results show that this unit can indeed power a single 8800 Ultra card, and the 12v rail varying by 0.1v. This is quite a large tolerance, but this PSU shouldn’t be able to do what we asked; moving by a tenth of a volt isn’t a bad result at all. The other rails were more or less 100% stable.

While all the rails are well within ATX specifications, the 12v rail is a little high, especially at idle. While it’ll have no impact on system performance, the golden 12.000 mark was missed by 0.355v.

The main selling point of this power supply is its noise output, which is indeed next to nothing. Even at full load, the ZM500-HP never exceeded a whisper volume which is fantastic, especially for anyone who has a media PC.

Zalman ZM500-HP
Click to enlarge
Zalman ZM500-HP
Click to enlarge

The PSU has blue LED’s ‘for cool aesthetics’. I’m pretty sure that there is only one tiny LED in the unit, it’s what marketing would call ambience and I would call crap. It’s so weak as to be pointless and more than likely annoying. If you’re going to light a PSU, either go for bright LED’s or nothing at all.


The ZM500-HP does exactly what it sets out to do, which is to power your PC without your ears knowing about it. The fairly low wattage won’t excite the gamer, but is more than sufficient for a media PC or a low/mid-end gaming machine. The SLI sticker on the box seems misleading, but the 600w version will do the trick for multi-GPU owners.

If you find yourself annoyed with power supply noise, and want fairly stable rails, have a look at the Zalman ZM500-HP; it might just be perfect for you.

Pros Cons
Good rails No kettle lead
Silent Underpowered
Blue LED??? Little bit more expensive than other 500W PSU’s

I’d like to thank our sponsors QuietPC for providing us with this PSU.

Discuss this review in our forums.

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