Cooler Master Seidon 120M Review Page: 1

 Cooler Master Seidon 120M Review  



Water cooling, once the preserve of the pro/enthusiast is becoming more mainstream.  With prices falling and mounting systems becoming simpler AIOs are starting to catch the eye of those of us who think of ourselves as mere mortals.  With this proliferation you might be wondering then why it's taken a company such as Cooler Master all this time to bring a range of AIOs to market.  Well it could be because Cooler Master have chosen not to outsource the design and manufacture of the Seidon range, opting instead to keep the whole process in house.  No CoolIT or Asetek clones here, not that there's anything wrong with either of those designs, it's just nice sometimes to see a manufacturer put their money where their mouth is.  Time well spent?  We hope so, but just because it's their own work doesn't mean it's any good.  We're an even handed bunch here at OC3D and just because a firm has a good track record doesn't mean to say we automatically assume their products are all going to fall perfectly formed and delicious like manna from the heavenly table of PC components.  Look back through the reviews and you'll see that many is the time a company renowned for producing pure perfection has produced what can at best be described as pure Poo.  As the smallest sibling to the 120XL and 240M, the 120M enters the market at a very competitive £43.  Inexpensive without doubt, and well into the territory of traditional tower coolers.  How then will the Seidon 120M perform?


Technical Specification


Ø 70 x 27mm (Ø 2.75 x 1.1 inch)

Intel Socket

Intel socket 775, 1155, 1156, 1366, 2011

AMD Socket

 FM1, AM3+, AM3, AM2

Radiator Dimensions

150.3 x 118 x 27mm (5.9 x 4.6 x 1.1 inch)

Radiator Material


Fan Dimensions

120 x 120 x 25 mm (4.7 x 4.7 x 1 in)

Fan Speed

600~2400 RPM (PWM) ± 10%

Fan Air Flow

19.17 ~ 86.15 CFM ± 10%

Fan Air Pressure

0.31 ~ 4.16 mm H2O ± 10%

Fan Life Expectancy

40,000 hours

Fan Noise Level (dB-A)

19 ~ 40 dBA

Fan Bearing Type

Rifle bearing

Fan Connector


Fan Rated Voltage

12 VDC

Fan Rated Current


Fan Power Consumption


Pump Life Expectancy

70,000 hrs

Pump Noise Level


Pump Connector


Pump Rated Voltage

12 VDC

Pump Load Current


Pump Power Consumption







Cooler Master Seidon 120M Review Page: 2

Cooler Master Seidon 120M Review


Packaging and Contents

The Seidon 120M is presented in a predominantly black box but does of course sport the well known Cooler Master Purple panels.  The rear of the box gives the usual specs and features with the front being given over in the main to a nice arty shot of the cold plate with the rad in the back ground.  

Cooler Master Seidon 120M Review     Cooler Master Seidon 120M Review


Opening the box we find that Cooler Master like many other manufacturers are moving away from vast chunks of polystyrene in favour of more Eco friendly reconstituted cardboard.  The layout is similar to that of the Corsair H60, however Cooler Master have allowed much more room between the various contents and as such the box is bigger and a lot less cramped.  Each of the items comes sealed into its own zip lock plastic bag, and each sits in its own compartment.  Cooler Master provide fittings for pretty much all current CPUs from both Intel and AMD, with socket 2011 fittings being included in their own little bag to avoid any confusion.  A small syringe of Cooler Master TIM is also included in the box, although as always we shall be using our Noctua TIM.

  Cooler Master Seidon 120M Review     Cooler Master Seidon 120M Review


The instructions for the Seidon 120M are similar to those included with other Cooler Master products and it has to be said aren't as clear as those we see with other manufacturers.  A small strip of images down the left side of the sheet which folds out to the size of a small duvet cover are accompanied by columns of written instructions in just about every language you can think of (excluding Welsh).  Those with aging or tired eyes will find them selves having to squint quite hard to see what's going on in the pictures.

  Cooler Master Seidon 120M Review     Cooler Master Seidon 120M Review  

Cooler Master Seidon 120M Review Page: 3

Cooler Master Seidon 120M Review


Up Close:  Cooler Overview

Although an all new design the Seidon treads a familiar path.  A slim rad measuring just 27mm in depth is coupled with a pump/cold plate assembly by means of 300mm corrugated tubing. 

Cooler Master Seidon 120M Review     Cooler Master Seidon 120M Review


If you're thinking the plastic corrugated tubing lacks the flexibility of some of the rubberised tubing seen on other coolers you'd be wrong.  It's ever bit as flexible and short of hitting it with a hammer guaranteed not to kink

 Cooler Master Seidon 120M Review      Cooler Master Seidon 120M Review


The Seidon comes with a Cooler Master fan (resplendent with a Cooler Master logo on one of it's blades).  The fan is a 600-2400 RPM model with manufacturers specifications rating it at between 19 and 40dBA.  Looks like at full tat we can expect this fan to produce a little less than a gentle susurration. 

Cooler Master Seidon 120M Review      Cooler Master Seidon 120M Review  

Cooler Master Seidon 120M Review Page: 4

Cooler Master Seidon 120M Review


Up Close:  Cold plate and Radiator

The Aluminium Radiator of the Seidon measures 150.3x118x27mm so is just a fraction thicker than your average 25mm case fan and strangely a little narrower across at only 118mm.  The two end tanks, with the tubing attachment end being a little bigger than the other give the radiator an overall length of 150.3mm, 35mm greater than that of a case fan.  Aside from being extremely interesting, these measurements are critical to you if you are planning to put the rad directly inside the rear extract position with the fan internal to the radiator acting as a pushing extract.  If that's the way you mount the set up, and it's the way we mount them, then make sure you have sufficient room at the rear of your case to do so.  The tubing is connected to the rad on one side of the larger end tanks either side of the centre line.  What we assume to be the manufacturers fill port lies to the far end with a tempting sticker urging us not to tamper with or remove it, although it does appear to be pointing at the space between the port and the tubing insertion.  If you're looking for a quick way to void your warranty you just found it.

Cooler Master Seidon 120M Review     Cooler Master Seidon 120M Review


The rad has 12 visible water channels with no immediately obvious damage to the fins between them,  We say this as it is not uncommon for rads to arrive with the consumer with bent or buckled fins.  No such problems here then.  There are mounting holes on both sides of the rad for the attachment of 120mm fans and Cooler Master have very thoughtfully included additional bolts in the accessories bags to enable this.

 Cooler Master Seidon 120M Review     Cooler Master Seidon 120M Review  


The cold plate although low profile looks quite rugged and chunky, with the Cooler Master name having the appearance of having been stamped into the back.  Contained in all this chunkiness is a small blue LED which subtly lights up the back of the cold plate when the pump is running.  The Tubing attaches via 90 degree elbows, with each elbow being able to rotate some 45 degrees in either direction.  A smartly braided power cable exits the cold plate from the side of the cylindrical edge.

Cooler Master Seidon 120M Review     Cooler Master Seidon 120M Review


The circular copper contact plate is smooth, having a slight brushed look to it, and with 12 screws holding the assembly together we think the chances of a leak here are next to zero.  Although circular the contact plate is plenty big enough to cover the heat plates of the CPUs specified. 

Cooler Master Seidon 120M Review     Cooler Master Seidon 120M Review 

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 Cooler Master Seidon 120M Review


The Build

Although  the instructions aren't the clearest in the world, and depending on the quality of your eyesight may require you approach them Sherlock Holmes style with a magnifying glass, they are, none-the-less, sufficient enough to enable even the most ham-fisted amongst you to get the job done.  Just expect to do a lot of squinting.  The parts come bagged and labelled with it being fairly easy to determine which bit's you've going to need for your chosen CPU.

Job one is to attach the retaining brackets to the Cold plate.  The Intel and AMD ones do look very similar and both attach in the same way by means of 4 small grub screws passing through from underneath. 

Cooler Master Seidon 120M Review     Cooler Master Seidon 120M Review


Next up is to screw in the Motherboard retaining bolts.  If you're using anything other than 2011 then you'll also be screwing through to a back plate at this point.  Cooler Master have provided a socket with a screw driver adaptation to allow you to get them tightened down.

  Cooler Master Seidon 120M Review     Cooler Master Seidon 120M Review  


Remembering to add your TIM (all too easy to forget in the heat of the moment), the cold plate is carefully lined up with the retaining bolts.  Sprung loaded screws on each corner of the cold plate bracket are then pushed down and tightened with a screwdriver.  It's a bit of a fiddle as there's a propensity for the cold plate to want to skate about a bit at first, and although there are better mounting systems out there, there are definitely worse.

Cooler Master Seidon 120M Review     Cooler Master Seidon 120M Review


If you're setting up the Seidon on extract with the fan internal on push, which is how we do it, then the next job on your list is to use the provided short screws to attach the rad to the case from the outside.  The fan is then attached to the rad by utilising longer pass through screws from the inside.  As Cooler Master provide an additional set of these longer screws it's a relatively easy task to add another fan in push pull configuration.  When we talked about the radiator earlier we mentioned the importance of checking the dimensions and clearance.  the image below left shows the small amount of room between the end tank and the expansion card recess in our Cooler Master Storm Trooper case.  Should your case not have sufficient room, all is not lost, it just means you'll have to mount the fan to the case using it as a spacer to enable the rad to be fitted.  in this configuration it's still possible to have a intake or extract set up.

  Cooler Master Seidon 120M Review     Cooler Master Seidon 120M Review  


The flexibility of the tubing and the rotating 90 degree elbows as they join the cold plate assembly make the task of routing the tubing an easy one.  At 30cm the tubing is long enough for most cases without being so long as to make things look messy (We're looking at you Swiftech).

Cooler Master Seidon 120M Review     Cooler Master Seidon 120M Review


As with all our testing we hook the fan and the pump up to a 12volt supply straight from the PSU.  Both the pump and the fan can be attached to the motherboard or fan controller via fan headers but in the case of the pump this really isn't necessary as it runs pretty much silently even at the full 12 volts.  The fan is PWM compatible so if you choose it can be controlled by your Motherboard.  Both cables are 32cm long including the plug and are braided in black.  Seen here inside our loyal Cooler Master "Test Trooper" we think you'll agree the Seidon makes for a tidy build.

 Cooler Master Seidon 120M Review     Cooler Master Seidon 120M Review


All assembled then and time for some low light shots to show off the subtle blue LED built into the cold plate housing 

 Cooler Master Seidon 120M Review     Cooler Master Seidon 120M Review  

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Cooler Master Seidon 120M Review



Intel i7 3960X [email protected] 1.1v (undervolted) 4.0GHz @ 1.25v 4.4GHz @ 1.35v 4.6GHz @ 1.45v Gigabyte X79 UD3 Corsair Vengeance LP Memory Corsair HX850 V2 Corsair Force GT 60GB Coolermaster Storm Trooper


As usual we'll be testing our coolers at varying  levels of overclock and increasing levels of voltage.  this in turn of course means increasing levels of heat which the coolers need to dissipate.  To begin with we start with the undervolted stock speed.  Why undervolted? well if you have things set on "Auto", you may well be using more volts than are actually required to run at the chosen frequency, for example our 3960s will run quite happily at just 1.1volts, solid as a rock, 24/7, and as such we use this as our starting point.

Continuity is very important in testing, and for this reason we keep as many of the potential variables as locked down as possible.  We will be using OCCT in Linpack X64, AVX compatible with all logical cores tested and 90% free memory utilised. The test is set up to run automatically with just a few clicks to set it going.  A 10 minute idle followed by 30 minutes of testing and a 5 minute cool down is the order of the day and brings the total test time per clock speed to 45 minutes.  So as to remove subjectivity in determining whether a CPU has failed, OCCT is set to stop the test and register a fail should the max temp exceed 80 degrees.  In testing we noted that if even just one of the cores exceeds 82 degrees OCCT halts the test and a fail is recorded.


Turning now to the 4GHz test we up the voltage to 1.25 volts, this is what is deemed normally as stock volts. Something we are always harping on about on the forums is AUTO does not mean stock volts, and normally if you overclocking with "auto" volts the motherboard will be upping the volts much more than needed if you were to do it manually. By whichever means it happens, upping the volts (especially from our 1.1v undervolt) does have a big impact on temps, with an average increase of 10-15 degrees seen in the results.



Upping the volts still further we achieve a stable 4.4GHz overclock at 1.35 Volts. It's here we start to separate the wheat from the chaff, with lesser coolers not able to disperse the increased heat effectively. Again we see a jump of 10 degrees or so from the figures at 4GHz. Both the H100 and the well respected D14 are creeping into the 70s here, indicating that only the cream of the crop will excel at this level. 



With the temps being only slightly better than those of the Corsair H60 we weren't really expecting the 120M to make it through the hardcore 4.6GHz test, and guess what, it didn't!

Cooler Master Seidon 120M Review Page: 7

Cooler Master Seidon 120M Review



Although it's taken them a little while to get out of the blocks, Cooler Master have produced what appears to be a decent little AIO water cooler.  In using a slim 27mm radiator and single fan allied to a cold plate by means of flexible corrugated tubing, Cooler Master have stuck to a well established recipe.  The Seidon 120M however is all their own work, with both design and manufacture being kept in house.

There is certainly quality evident in the manufacture and presentation of the components, no small feat given the £40 price point of the unit.  You get the feeling that savings have been made, rather than corners cut.  Heck, there's even a bit of bling in the form of the Blue LED on the pump top.  If you want high gloss aesthetics and rubberised tubing you need to look elsewhere.  However if you're fond of rugged simplicity and a design that looks like it was the product of an engineer as opposed to an artist then the Seidon does have a certain appeal.

Assembling and building with the Seidon 120M isn't as easy as with some AIOs, Corsair's new magnetic mount in particular taking the ease of build crown.  That said it isn't exactly hard to put together either, just remember to get the magnifying glass out to look at the diagrams in the instructions.  For those of you who haven't leafed through the full review (shame on you) the fitting process requires crescent shaped mounting brackets to be attached to the sides of the cold plate.  The whole shooting match is then screwed down to the motherboard or back plate (depending on the CPU) utilising captive sprung loaded screws mounted into the brackets.  Cooler Master even include a small syringe of TIM which should be good for 2-3 fittings should you choose to use it.

The Seidon performs well beating the recently reviewed H60 by a small margin at all clock speeds.  The slightly better performance could in part be down to the Seidon's higher RPM fan which at 2400RPM producing a max of 40dBA is also noticeably noisier than Corsair's fan which spins at a max of 2000RPM emitting a maximum of 30.85dBA.  Fan performance aside, at the end of the day it does beat the H60, if only by 10ths of a degree at times.  Remember that we test all set ups at the full 12 volts and as such show you the maximum that each is capable of.  We accept that if you slow the fan down then the noise will drop, but conversely the temperatures will climb.  Not a problem if you're just bimbling about on the web, but more of an issue if you forget to turn things back up before you go gaming.  The Seidon did fail the 4.6GHz test, but we didn't really expect it to pass.  It did however make it considerably further in than the H60 before hitting the fail point of 80 degrees max and thus stopping the OCCT test dead in it's tracks.

At a smidge over £40 it's hard to think of a cheaper way into effective water cooling.  In fact if you take the time to trawl around the numerous sales sites on the web we think you might agree that it would be quite a strange decision to opt to purchase a traditional tower air cooler at this price point.  It's unlikely any will get close to the performance achieved by the Seidon, and those that do will not doubt be of such megalithic proportions as to be causing you RAM encroachment issues.  You can of course get better performing AIOs, they are though, I goes without saying, considerably more expensive.  If you're going to want a massive overclock or very quiet running fans then you're going to need to spend over twice as much money as the £43 needed here.  

They may have taken their time, but we think Cooler Master have spent it well and have perhaps succeeded in making water cooling accessible to those on a very tight budget and for that reason we have decided to bestow it the OC3D Value for money award!


Thanks to Cooler Master for the Seidon 120M, you can discuss your thoughts in the OC3D Forums.