Zalman PWM Mate Review

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Plenty of overclockers use fan controllers. With each controller we sweat the Watts each channel can control, and calculate how many fans we can put on a single channel. What if we didn’t have to worry about that? That’s why Pulse Width Modulation was imported into fan control.

Introduction to PWM

Almost all motherboards can control fans with PWM, which stands for Pulse Width Modulation. A PWM fan has the normal three wires — ground, 12 V, and RPM reporting — and an additional 5 V control line. The PWM control line varies in its “duty” from zero to 100%. The intermediate settings are made with 5 V pulses that signal the circuit board of a PWM fan to tell it how fast to spin. You can emulate a zero duty state by poking a grounded wire into a PWM plug’s PWM control line. You can emulate a 100% duty state by poking a 5 V wire from the PSU into a PWM plug’s PWM control line. What you can’t do that way is produce the intermediate settings.

Motherboards can, and do, produce those intermediate settings to control PWM fan speed. If you have a heatsink with a PWM fan and you have set it to Auto you will hear the fan speed up from slow to fast as your CPU proceeds from idle to load.

Some PWM heatsinks come with PWM Y-cables that allow two fans to be controlled by PWM. Akasa makes PWM harnesses for three and five fans  so you can control a number of fans with the motherboard. In the case of the Akasa PWM splitters, the power for the fans comes from the PSU via a Molex connector, so you don’t have to worry about overloading your motherboard fan header. Having such a PWM splitter would allow water coolers to have their fans respond to the cooling needs of their CPU’s. I use my PWM splitter to increase the air being fed to my CPU heatsink when it needs more. It’s really an elegant way to adjust your fans automatically.

What if you want to control your PWM fans manually? Zalman has just what you’re looking for, the PWM Mate.

Specifications & Features

(Courtesy of Zalman)

Zalman PWM Mate Specifications
Dimensions 55 x 24 x 13.5 mm
Weight 12 g
Output PWM Duty 25-100% ± 5%
Connector 4-pin
  • The World’s First PWM Fan Speed Controller – The controller modulates the PWM (Pulse Width Modulation) fan speed control signal allowing user defined PWM fan speed settings.
  • Variety of Control Modes – The 3-Step Automatic Mode and a Manual Mode provide flexible customization of fan speed control according to the user’s environment.
  • Convenient Controls – The Mode Switch Button, Manual Speed Dial, and Mode Indicator LEDs provide convenience and ease of use.
PWM Mate
PWM Mate

That articulated cover on the left is a push button. The dot to the left of the green light is a two-color LED. When you press the button, you get a blue light in the left LED that tells you the PWM Mate is pulsing at 50% duty. When you press it again you get a magenta color (blue + red) in the left LED that tells you you’re getting 75% duty. Press it a third time and the left LED shines red. Now you’re at 100% duty. Finally, press it a fourth time and you’re back to the right LED shining green, which means you’re in manual control mode. Twist that little knob on the right and you get a pulse duty range of 25% to 100%. Very simple, and it works.


PWM Mate with fan
PWM Mate with fan

Here is a fan plugged into the PWM Mate. You can see the plug that fits into a PWM fan header. That’s where you get the 5 V needed to run the PWM control. Be sure to have your motherboard’s speed control disabled.

How well does it work? I plugged the PWM Mate into an adapter I made so it can get pure 5 V and 12 V from a PSU. As best I can tell, the knob turned all the way counterclockwise delivers a 25% signal. When the blue light is lit I seem to get a 50% signal; magenta is 75%; red is 100%. Green, with the knob turned all the way clockwise is 100%. The 25%, 50%, and 75% are all approximations. All fan’s PWM runs at whatever speed they are programmed. It doesn’t have to be linear.

What surprised me is that the 100% settings are exactly 100%. My experience with motherboards led me to expect speeds that were 90-95% of what the fan gets when it is on pure 12 Volts. This little controller gave me 100%. What a lovely present Zalman has delivered! The PWM controller works exactly as advertised. I’m impressed.

Here is a PWM Mate hooked up to a motherboard’s CPU fan header:

PWM Mate hooked up to a motherboard
PWM Mate hooked up to a motherboard
You can also see two fans connected with a Y-cable. Note that socket where the Y-cable is plugged in. The white wire and the wire next to it are the ground and 12 V wires. They are split at the socket, so the controller gets a ground and a 12 V power supply. But the fan or fans get the same, and their ground and 12 V supplies run directly to the fan, not through the PWM Mate. Hold that thought.

What the PWM Mate Needs

This little fan controller is great. Is anything wrong with it?

Yes. Well, no. But it needs something. It needs an adapter so it can get its power from the PSU, via Molex. That way it could power fans that draw more current than a motherboard can supply. As it stands now, you could burn out at least the fan power circuits of a motherboard if you tried to control a heavy duty fan with the PWM Mate hooked to a motherboard’s PWM header.

Okay, that thought you were holding. A fan gets its 12 V power and its ground connection without bothering the PWM Mate. So, with the right connections (sounds like New Jersey, right?) you could power a heavy duty fan, control it with the PWM Mate and leave the motherboard out of it.

Pardon the mess, but here is such an adapter:

PWM Mate with fan and adapter
PWM Mate with fan and adapter

Next to the fan you can see the Molex connectors. Swooping counterclockwise from there is the sleeving that contains the 12 V, 5 V, and ground wires. It ends where it meets the PWM Mate’s plug. Running back clockwise again is the yellow RPM wire that allows the fan to report its speed to any fan header. This adapter allows me to connect the PWM Mate to 12 V and 5 V power from PSU. With this adapter I can attach a fan that would otherwise overdraw a motherboard’s fan header.

In place of my adapter I could plug in a PWM splitter. That would allow the PWM Mate to control a lot of fans — a whole rad full of fans, for example. And because a PWM splitter draws its power directly from the PSU, a PWM Mate could control some powerful fans that would burn out any little plastic box, if they tried to draw their power there.

That’s what this little gem needs. Can’t expect everyone to make their own, and not everyone needs a PWM splitter. I understand why Zalman made it the way they did: the PWM Mate got its start as a PWM controller for one of their heatsinks. But an adapter similar to the one above makes it far more versatile.


I am mightily pleased with my PWM Mate. It works as advertised, and I recommend it.

  • It’s dead easy to connect.
  • The knob gives you a smooth adjustment in PWM duty from 25% to 100%.
  • The button gives you 50%, 75% or 100% duty with a few quick clicks.
  • This controller really does give you full speed (100%) when you want it.

With power from the PSU and a PWM splitter, the PWM Mate can be an even more useful controller. Here are five PWM fans plugged into an Akasa FP5 — a 5-way PWM splitter. The FP5 is plugged into the PWM Mate. The FP5 and the PWM Mate are plugged into the PSU. All of this allows me to get PWM variable speed control on five fans with nary a motherboard in sight.

Five PWM fans with PWM Mate and FP5
Five PWM fans with PWM Mate and FP5

Note to Zalman, if you are reading this: add an adapter like the one I made and your little box can control even monster fans. Not having an adapter is not really a downside. It’s a missed opportunity.



Leave a Reply

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  1. I tried a similar setup and I could only fully control 3 PWM fans, not 5. As soon as I connect the 4th fan the PWM Mate can only reduce the speed of the fans by about 90%. Unless I did something wrong?
    1 - I connect a 4pin to 3pin molex adapter to the PWM Mate link this one:
    2 - Then connected the Akasa 5 fan splitter to the PWM Mate.
    3 - As soon as connect the 4th fan, the PWM Mate stops fully controlling all fans. When I play with the dial, I only sense the fans slowing down slightly. When I just leave 3 fans connected, the PWM Mate controls the fans as advertised.
    (I hope this is the right section ...)
    I'm new on this forum but I have read various articles with pleasure.
    I submit my problem:
    I'm doing a wooden cabinet that will contain my pc, and I would like to provide it with an independent ventilation.
    As a fan I chosed the gentle typhoon at 3000 rpm (D1225C12B7AP-29).
    3 for extraction and one for the internal recirculation (the introduction of air is passive ..).
    My aim is to be able to power these fans with an external power supply (not computers) independent and be able to adjust the speed indipendently of the group from 3 extractor fans and one for recycling.
    After ahving done my homework I have come to this configuration:
    Apply to all the fans 4 modifcation for control via PWM signal.
    Universal switching power supply 12V 3A with 3 plug (part number HB030) connected to the power of 3 extractor fans in parallel (by connecting the respective additional molex).
    Switching power supply 12v 2a 3-5 plug for hdd (code HB200) connected to outlet type "Internal Power Y-Cable 4-pin molex 12v" with the two ends connected to two Zalman PWM Mate.
    One of the two pwm mate will go directly connected to the single ricirculation fan and give power and the control signal.
    From Second pwm mate i'll take only the PWM signal control to regulate the 3 extraction fans.
    Now I ask you, apart from the reasons for the cabinet construction, the choice of the fans and the type of use...
    If i connect this configuratio i will risk an "explosion" of my precious fans or of the pwm mates?
    power supplies are properly sized according to you?
    The pwm mate is able to simultaneously control the three fans?
    you can feed the entire system with a single power supply? if so what is it?
    are 2A too much to feed a pwm mate? what should i use?
    Thank you in advance for any reply and I apologize for possible nonsense.
    @niikovac -
    What you describe sounds reasonable. Just make sure you feed the PWM Mate 5 Volts at the appropriate wire. It modulates 5v to control the fans.
    The fans take 12v to power themselves. Don't get the two different Voltages going to the wrong places, and you should be all right.
    And as for resurrecting the thread: most folks look down on the practice. I don't mind it for my threads. In fact, your proposal may be the right use for PWM Mates.
    Be sure to keep a build log. Post some pics here, along with some links to the log.
    Hello, thank you for your reply and your very informative article. Unfortunately the only mail-order I've found in Europe with the pwm mate in stock told me after a week that this product is unavailable and discontinued. I don't have any official news on it, but today i can't find a place to buy it in Europe. I was hoping to use this solution instead of voltage regulation believing it would be more efficient, but not this time, i hope that this product or something similar will be available in the future. For now I will go with a 30W per channel rheobus , hoping it will not create too much heat.
    @Niikovac - I'm ordering PWM mates and I can order an extra one for you, if you would like. According to your nickname, you are probably somewhere near :) Send me an email.
    @ehume - your posts are great, however I am not quite sure how to do the wiring for my application of the PWM mate. I would like to control 4 fans without a PC - only with power supplies. Can you please comment, wheather my wiring is correct...
    You have PWM fans? If so they will run at full RPM unless you have a PWM signal to each fan and no need for 5v either.
    I don't see a PWM input to the fans. If they are voltage controlled fans just get a fan splitter, cheaper.
    Each PWM Mate has a plug and a socket.
    Plug > Ground (white) > socket > gnd (white) > PWM Mate
    Plug > 12 Volt (black) > socket > 12v (black) > PWM MAte
    Plug > RPM (black) > socket (signal comes from fan to socket to plug)
    Plug > PWM (black) (skips socket and becomes 3d wire to PWM Mate) > PWM Mate
    Socket (4th wire) < PWM Mate
    So the plug, the socket and the PWM Mate all have four wires:
    Plug is gnd/12v/RPM/PWM
    Socket is gnd/12v/RPM/PWM
    PWM Mate is gnd/12v/PWM-in/PWM-out
    Your PWM splitter's plug goes in the PWM Mate's socket.
    ehume, what if he has PWM fans and no speed signal? He's not using a PC so he has not PWM to control the fans. Wouldn't it be cheaper to get a fan splitter that can handle 2A that will accept a 4 pin connector?
    They will run at full RPM anyway........
    thanks for the replies. I understand the wiring of the PWM mate now, however I am not sure how to control the fans without a PC // motherboard.
    1., 2. and 4. wire from PWM mate goes directly to the 1., 2., and 4. wire of the fans - is that sufficient or do I have to have something additional for the PWM in (3. wire on the PWM mate)?
    I am not using the standard plugs and socket on the PWM mate, therefore only the connections on the PWM mate are important to me.
    And yes I am using the 4-pin fans, because they came along with the heat sinks I bought. Otherwise I would rather have 3-pin fans... These 4-pin fans in my case don't work at all, if I plug them in 12 V.
    Any ideas, whether it is possible to control 4-pin fans without a PC?
    Without a square wave of some frequency you won't be able to control the speed. You can make your own speed controller so you don't need a PC. The post on how to do it is right next to this one.
    Dudes . . .
    If you provide the PWM Mate with 5v power, that is enough. The PWM Mate creates its own PWM signal. This:

    I have five fans controlled by the PWM Mate. (My FP5 PWM splitter only controls 5 fans; if you get the Swiftech 8-fan PWM splitter you ought to be able to do better.) Notice in the back. One of the two higher-up fans is sitting on the PSU. There is no motherboard there. When I took this shot the motherboard was twelve feet away and not connected to this at all.
    I was a little quick with my conclusions :)
    The fans work without the controller on 100% power.
    The controller works without the 5 V suplly, however it can control only one fan or maybe two. Does anybody have an idea what do I have to do, to control four or more fans?
    The problems may be arrising from the fact I have a switch adapters for 12 V and 5 V. Would a steady 12 V and 5 V solve the problem or is there something else?