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Corsair HydroCool200EX Water Cooler Review

Key Specifications

  • Review Price: £164.00

Anyone who has been following the evolution of the CPU must surely be wondering how on earth we’re going to keep these high-powered silicon workhorses cool. The problem lies not only in their ever-increasing power requirements but also in the fact that they have a limited surface area from which to radiate the heat this generates.

Since the birth of computing, air has been the coolant of choice, but its limitations are finally beginning to be realised. Not only are heat sinks are getting bigger and bigger leading to inevitable concerns over their weight, cooling fans are also having to spin ever faster to generate increased airflow, which of course means elevated noise levels.

The solution is quite a simple one, and though you’d be forgiven for thinking otherwise there’s actually no black magic or experimental science involved. I’m referring to water, a substance that, considering it plays such a vital role in life on earth, seems to have a strangely villainous reputation when it comes to cooling our computers.

Take a look at any enthusiast orientated hardware retailer’s website and you’ll find a wide selection of water-cooling products for sale. Some are aimed quite squarely at experienced users who are expected to plan the layout and assembly to suit their particular chassis, while others offer a more compact, user-friendly approach, often at the expense of the overall performance levels to some extent. Very few products manage to successfully incorporate efficient cooling into a product that almost any level of user can get to grips with, while those that do often lack those reassuring safety features that help the new user come to terms with the disconcerting knowledge that disaster is just a pump failure or a serious leak away.

The HydroCool200EX is a rare bird in that it claims to offer all the benefits of a self-contained, chassis independent cooling product with more advanced features such as low fluid level alarm, user definable fluid temperature alarm, visual flow confirmation, temperature readout, thermally controlled fan with override, emergency shutdown function and self diagnostic routine. Designed in tandem with transportation components and systems technology giants Delphi – is this the ultimate foolproof water-cooling kit? Let’s see.

Naturally my first action once I received the HydroCool200EX was to remove the four screws that secure the outer casing and take a look at what lurked beneath. As a rule my priority when appraising any water-cooling kit is the pump, and on this score I was pleasantly surprised. Corsair has opted to use a relatively expensive Bosch PAD type PA66 pump. Rated at 15 Litres per minute it doesn’t sport the highest flow rate you’ll find but provided the radiator and CPU water block are well matched this will not be a problem.

The PA66 is a magnetic drive pump; meaning the motor and impellor are coupled magnetically and need no physical drive shaft between them. Mechanical drive shafts need to be sealed to keep water out of the motor casing so of course using a magnetic drive makes for one less potential source for leaks. The motor itself is a 12-14V DC brushless unit and the whole assembly has a very commendable 10,000-hour estimated lifetime. I say commendable because in pump terms it’s a pretty good rating, but that actually translates to only 417 days of 24-hour use which sounds slightly less impressive. The pump was designed to handle a normal ethylene glycol and water coolant at temperatures up to 100 degrees Celsius, though if your coolant ever gets this hot I’d suggest something is seriously wrong somewhere, not least with the emergency shutdown!

The radiator is an all Aluminium affair with cylindrical tanks on either side rather than top and bottom. It has a very tight matrix, which should really help dissipate the heat. It will also have a tendency to clog rather easily with dust, making the two air filter assemblies that the HydroCool uses all the more critical. A potent looking 120mm fan provides the airflow. This was unbranded so far as I could tell.

The interior layout of the HydroCool is neat and tidy with all the pipe work thoughtfully routed. My only complaint is the slightly shoddy way in which the reservoir has been riveted to the rear wall of the unit. I could easily rock the reservoir a little laterally and though it wasn’t vibrating at the time of testing, the potential exists.

At this point I replaced the cover and took a look at the unit as a whole. The cover is actually manufactured from a very dark coloured Perspex that doesn’t offer much of a view inside under normal daylight but which seems to become magically transparent in low light. Then the bulb used to backlight the flow meter illuminates the internal workings of the HydroCool. The black, gloss finish combined with the chrome fan grills either side and the chromed carry handle on top do make for a reasonably stylish, if slightly boxy appearance.

Considering the plethora of features on offer the HydroCool is fairly low on external ports and plugs with nothing more than a couple of quick-release pipe couplings and a 15-pin data connector on the rear panel and a metal filler cap on top. This, plus the carry handle, a quartet of buttons, a red LED display and light on the front panel and the four rubber feet used to isolate the unit from whatever it may be stood on pretty much wraps up the external paraphernalia.

Next in the plan of action was to get the HydroCool installed. A quick rummage for the printed manual turned up nothing more than a slightly vague quick-start pamphlet that covered the basics but in no great detail. Moments later my heart sank as I realised the detailed info was to be found only on the supplied CD. I find it slightly bizarre that detailed instructions for a routine that must be carried out with my PC powered down can only be accessed with my PC powered up.

For me, the first step was to install the controller card into an available expansion slot. This is a self-contained PCB that doesn’t require a PCI slot in order to function. While this means you can use any free expansion slot, the feed and return pipes also pass through a pair of grommet-equipped holes in the bracket so you won’t want to site it too far away from your CPU for ease of routing the pipes.

Four connections are required to the controller card. A power feed from a standard four-pin Molex plug, the wire from the water block’s thermistor which provides temperature data, a feed to the motherboard’s power switch pins to facilitate emergency shutdowns and finally the 15-pin data cable which shuttles data between the card and the main unit. The emergency shutdown operates by sending a command to the motherboard equivalent to having pressed the power button on your case, so in order for this to actually perform a full shutdown you may have to enable this option in your BIOS.

Installing the water block was by far the most difficult part of the operation. I mean difficult as in fiddly rather than mentally challenging though. This is more of a problem with Athlon 64 boards where you need to attach the retainer and the standard heat sink retaining frame on longer screws but with small plastic spacers between them while trying to keep a couple of springs in place. The challenge is to complete the operation alone without swearing. I failed!

The water block is made entirely from copper, which is then silver-plated to increase heat transmission and to deter oxidisation. It also features Delphi’s proprietary Microchannel technology designed to increase the internal contact surface and thus speed heat transfer from the block to the coolant.

Don’t try to fit the Athlon 64/FX retainer without the existing HSF retainer in place or you’ll likely break something or strip threads, and make sure the retaining frame is located properly over the motherboard lugs, if there are any, as you tighten. I also used a small mirror to confirm that the pressure springs were positioned correctly when I’d finished. The instructions with this bracket aren’t sufficiently detailed and ideally need to be redone with a bit more clarity. Better yet the bracket should be redesigned. AMD has introduced an improved retention mechanism so why not use it?

With the electrical connections complete and the water block securely positioned over the CPU, it’s time to connect the PC to the HydroCool. This means plugging in the data cable and then the feed and return pipes which, for the record, are 1/4in ID. A really clever touch is that, even when filled, you can unplug these two pipes from the back of the HydroCool without draining your coolant as both ends seal themselves when separated. There is a tiny bit of leakage as you separate them but nothing significant. The feed and return pipes can be connected any way around unless you’ve decided to add chipset or GPU cooling blocks in which case you’ll need to pay attention to flow direction. The higher of the two connectors is the feed to the water block while the lower is the return to the reservoir.

Speaking of filling, this is the next operation to be carried out. Corsair supplies a 150ml bottle of additive, which I believe is just anti-algae mixed with Propylene Glycol. Run without this at your peril as it prevents the Copper water block core reacting with the Aluminium radiator and causing widespread corrosion. A 1/3 additive to 2/3 distilled water mix is recommended.

After adding the entire bottle of additive, Corsair instructs you to fill the reservoir with distilled water and then fire up your PC. What on earth is Corsair thinking? If the pump is stuck or there’s a major airlock you risk destroying your PC in double-quick time. Considering this is no budget water cooler, I find it rather ludicrous that Corsair couldn’t supply an ATX power bypass plug to activate the power supply and allow the HydroCool to operate independently of the PC, at least until the coolant has safely circulated and the air has been expelled. At the very least Corsair should explain how you could achieve the same thing yourself with a short length of insulated wire. I use a paper clip but I’ve only myself to blame when it touches something and shorts out on me some day. I’m sorry, but instructing users to power up a PC when the coolant hasn’t even circulated yet is just asking for trouble.

After running the unit independently for about ten minutes to purge it of air, and to perform a quick check for leaks, it was time to plug the ATX block back into the motherboard and power everything up. The PC booted as expected and after a quick diagnostic routine the HydroCool flashed up a reading of 25C on the large, four digit LED display. As expected this slowly climbed as the coolant got warmed through before settling at around the 29C point. We need to remember that this temperature is taken from the top of the water block which is where the thermistor is located and is certain to be considerably lower than your actual CPU core temperature. In fact when the HydroCool was displaying 29C the Athlon was reporting a temperature of 38C. For this reason it’s best to think of the HydroCool’s reading as an indicator of general performance rather than a deadly accurate reflection of actual CPU temperatures. That said it might be useful if the HydroCool’s readout could be calibrated to match that of your CPU’s monitored temperature, not that that’s likely to be very accurate either.

The final step in the setup procedure was to set the two alarm temperatures. The first is used to sound an audible temperature warning and alert you that something may be wrong, while the second is the actual shutdown temperature. Pressing the “SET” button to the left of the display flashes up “AL 1” at which point you use the Celsius/Fahrenheit selector buttons to adjust the threshold up or down. You then repeat this for “AL 2” and you’re all done.

Although the HydroCool will automatically run the fan at 50 per cent full speed (Whisper Mode) so long as temperatures remain below 40C, it does step up to full speed (Turbo Mode) above this, you can also use the “TURBO” button to override the thermal monitoring and force the unit to run in Turbo Mode continuously should you wish. Noise levels are a subjective thing but I personally felt that the unit was very quiet in Whisper Mode but fairly intrusive in Turbo Mode. For the difference it made to temperatures I’d suggest you leave it in Whisper Mode and let it fend for itself.

The transition from air to water-cooling is more of a slow trickle than a raging torrent at the moment, but I believe it’s a transition that will have to happen failing the appearance of any new and alternative technologies.

Corsair has used its own marketing muscle and the vast experience of Delphi to create what amounts to one of the best self-contained water-cooling solutions currently on the market. Corsair has avoided any temptation to create anything too radical or eye-catching and gone for a simple, elegant and above all efficient design that actually works.

Performance levels are exemplary for this type of system, and while they don’t reach the lofty levels you could perhaps achieve from assembling your own circuit using handpicked components, it’s not a long way off. It could be argued that the HydroCool200EX is the proverbial jack-of-all-trades, master of none, but with systems as critical as water-cooling it’s not a master you need necessarily, but a loyal servant, a role that it would appear the HydroCool was designed and built to fulfil.


Efficient water-cooling systems aren’t that difficult to assemble, but the peace of mind that comes from being able to confirm coolant flow and temperatures at a single glance and from knowing that your PC Is protected by audible fluid level and overheat alarms and ultimately by an unattended overheat shutdown capability are what really sells the HydroCool for me.

The graph below indicates temperature in degrees Celsius while under load and idle. The HydroCool is compared to an Asetek WaterChill water cooler and an Ajigo heatsink/fan cooler. All temperature readings were taken from the motherboard thermal sensor.

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