INTRODUCTION
 
I often tell fellow enthusiasts that Corsair is probably the one company that you can think of as a constant in the PC DIY scene. Whether it is from good marketing or a steady stream of good products or a combination of both, they've been around since 1994 as a company and 2002 as a PC DIY solutions provider. This review of the H75 AIO came about more as a result of their HG10 A1 cooling bracket review which will be coming up real soon, and as with the NZXT x41 I wanted to test out the provided AIO as a CPU cooler first before strapping it on to a GPU die. Much thanks to James and George for providing the sample for testing!
 
Let's begin by taking a look at the specs courtesy the product page:
 


 
The 5 year warranty here pleases me because I have personally had only good customer support from Corsair on the rare occasions I have needed it, and so I can would like to assume this means 5 years of guarantee as well. We see this is a slim single 120mm radiator unit that comes with 2 of their SP120L fans in the package. As far as socket compatibility goes, as with most CPU coolers around, this will work with just about anything out on the market from Intel or AMD. Let's now take a look at the unit.
 
UNBOXING AND OVERVIEW
 


 
The product box (measuring in at 10.5" x 8.5" x 6") comes in a plastic sleeve around it and immediately recognizes the cooler inside. The outside does not do much to protect against scrapes and bumps necessarily but it will immediately show signs of any shipping damage.
 

 
On the back we see some specs listed out in several languages as well as the 5 year warranty mentioned explicitly.
 

 
On the bottom we get more tech specs as well as a comparison against the stock Intel cooler- something that most people have and can identify with but not necessarily a great choice for those looking for 3rd party cooling solutions. But then again that's the whole point of reviews like this so I understand where they were coming from.
 

 
On the side we get more specs listed out in different languages.
 

 

 

 
When you open the box, you are greeted to the H75 manual first and a soft foam sheet underneath. I like this for 2 reasons- (1) you are directly expected to take a look at the manual- which I do recommend people to go through if you are not familiar with the product, and (2) the soft foam provides some protection to the contents inside. The manual also contains the warranty policy pamphlet inside.
 

 
Removing the foam sheet, we are greeted to a standard cardboard (likely recycled material as well) box that contains everything you need in spaced out compartments.
Let's begin by taking a look at the provided accessories:
 

 
You get 2 of their SP120L 120mm fans and a pouch of mounting gear.
 

 

 
The fans are the OEM version of the popular Corsair SP120 non-LED fan, these don't come with vibration dampening corner pads or the colored rings to swap out at the front. These ones here also operate in between the SP120 Quiet Edition (QE) and High Performance Edition (HPE) as far as max fan RPM, noise, static pressure and airflow goes. But to further complicate things, there are also SP120L fans that come with other AIOs which operate at even greater speeds. We will cover those when we get to them with other coolers but for now here's a look at the SP120L 2000rpm fan specs courtesy the product page:
 

 
Not really much to go by, I would have liked to see some more detailed specs here about fans that come bundled with the cooler.
 

 
Ok, the label on the back of the hub helps out a bit. This is a brushless motor fan which usually means these were costlier to make and perform better than a non-brushless fan (a bearing fan) at the same noise level, but also means that the brushes eventually wear out. Given the various types of bearings used these days in fans, it is hard for me to make a global statement as to how brushless fans fare in general.
 
We also see that this is 12 V, 4 pin PWM fan that has a max listed current draw of 0.24 A (2.88 watts on a 12 V rail). In practice, both these fans here drew a max of 0.061 A each and 0.11 A together. Manufacturers tend to list a number higher than actual ones to be on the safer side so this is nothing new. So assuming each fan consumes ~0.7 W then even accounting for start-up boost, you should be able to power 10 of these off a single standard 1 A motherboard fan header and definitely the two accompanying the cooler.
 
Lastly, the hub itself measured in at 1.87" from the front and back. This is big enough a number where I would say a shroud would help reduce the effect of deadspots in airflow around the hub. The AIO radiator itself (Which we will get to soon) is a low profile one and so if you have the luxury of space inside your case, do consider a shroud between the fans and the radiator.

 
There are arrows on one side of the fan frame that point out the direction of airflow as well as the direction of the blade rotation. As mentioned earlier, there are no vibration dampening options for the corners or anywhere else here.
 

 
There is no sleeving of the cable done here, but each individual wire has a black insulation around it and the 4 wires are flat, ribbon style facilitating in cable management if in a tight spot.
 

 
The blades themselves are not much different looking than a standard static pressure optimized fan. The grey blade, black frame barebones aesthetics is consistent with a OEM/server applications perspective. The front has a Corsair sticker on it to give it some identity.
 
Now for the mounting gear:
 

 
You get 4 AMD socket posts which are black in color and in a separate pouch from the Intel gear.
 

 
The Intel gear contains the LGA 115x posts shown on the left, the LGA 2011/2011-3 posts shown on the right as well as the thumb screws which are to be used irrespective of the socket- Intel or AMD. Having these in with the Intel set potentially sends an interesting, albeit understandable, message.
 

 
The third pouch contains the screws and washers needed (8 each) needed to mount the two included fans on the radiator in a push-pull configuration if space is available. Alternatively, one can also just go with a single fan as well.
 

 

 

 
Lastly, you get the AMD mounting bracket (the Intel one comes pre-installed), the Intel LGA 115x/1366 backplate (AMD motherboards, and Intel LGA 2011/2011-3 motherboards have a stock backplate already) and a standard 2:1 PWM splitter to connect both fans to and run off a single PWM header. No complaints here as far as contents go, it is a standard Asetek set and takes care of all needs. 
 

 
The AIO unit itself has a plastic cover around the pump/block unit that also covers the tubing. Let's get that off for a better look:
 

 
Ah, that's better. We see the pump/block unit has another, harder plastic just on it to protect the cold plate as well as retain the pre-installed TIM.
 

 

 
The AIO unit itself is a relatively small one, with the tubing running in at ~13" only which is definitely something to consider as this will affect usage in a case- be it as a CPU cooler or as a GPU cooler using a bracket accessory such as the HG10.
 

 
The cold plate is circular in shape, as is the TIM pattern. The issue I have with pre-installed TIM is that you are limited to all of one installation, and I would really prefer having a tube or satchet of TIM on the side instead. Another potential issue is that you are now forced to do a one size, fits all solution irrespective of the CPU socket the user is on which doesn't work out great as we will see later. But then again the TIM used is a Dow Corning grease (Manufacturer part #1658832 I believe) which costs $950 for an 8 pound/3.6 Kg bucket. Before you go get a calculator to see how much a 1 gram tube would cost, don't- large scale economics do not work out on the small 1-3g TIM tube scale and this TIM is quite a lot more expensive compared to the usual aftermarket ones you can purchase. So I understand where Corsair is coming from as well since most end users only really use the cooler with a single CPU.
 
The 8 screws on the cold plate are flush with the copper surface and far enough that they do not influence the contact with the CPU IHS.
 

 
There are 2 rotary 90º barb fittings on the side on which the tubing is held on by plastic clamps which are meant to be removable. Given that I have only 1 sample here, I can't risk a disassembly but people have been able to remove them, swap the coolant and seal them again. I can't recommend this without any personal experience so this is a big case of YMMV.
 

 

 
The top of the pump/block unit has a plastic cover which when removed shows an elegant, clean design. No LEDs here, but see that ring? You can easily remove it and mod it to any color/texture/wrap as you want as seen in one of the Corsair in-house builds. The Hydro H105 actually comes with 3 swappable color accent rings (red, blue and the gray one as seen here) so I would have really liked to see the other two included with this cooler as well.
 

 
The tubing from the block/pump unit leads to fixed barbs on the radiator so that the fluid goes into the endtank, passes through the tube channels and completes the loop.
 

 
I counted 13 tube channels here in a single row, each of which had an average diameter of 2.2 mm and made of aluminum. The cold plate on the other hand is copper. There's a good reason the coolant is not seen anywhere in the AIO as even the best of anti-corrosive coolants can only really delay galvanic corrosion in the end. 5 years is probably ok though, and I am sure Asetek have though this through. There's also the part where most PCs are not on for the huge majority of time.
 

 
There is a product sticker on the side of the radiator which I suggest you not remove for warranty purposes.
 

 
The radiator construction is average at best, Asetek radiators have never really been a showcase for build quality. They do the job though, and once installed there shouldn't be an issue. This particular unit is only 25mm thick so the whole low profile aspect can be an advantage to those working in a small case.
 


 
The fins (again aluminum) came in at 22-23 FPI and an average thickness of 35 microns as measured by a micrometer. These are full serpentine fins and are slightly louvered so as to aid in air turbulence at high airflow.
 

 
There are no screw shields here but the tube channels are offset from the screw holes so any screws used that are longer than the provided ones will only bend some of the fins underneath and not pierce the channels. So there will be at worst some minimal performance loss but no chance of a leak. I still recommend using the proper screws only.
 
INSTALLATION
 
Let's begin with LGA 2011-3 since it is one of the easiest sockets to mount a CPU cooler on. Thanks to the attached backplate, you simply screw in the correct posts as identified previously into the 4 mounting holes on the socket:
 

 

 
Yes, those are Corsair DDR4 Dom Plats. More on them soon in a separate article! Once this is done, then simply place the cold plate over the posts:
 

 
The posts are not very tall so there is not much room to hold the pump/block unit in place. I wish this was not the case as I can see people having issues if installing this in a case with the motherboard already screwed in.
 

 
Screw in the thumbscrews two at a time (diagonally opposite sets) till the block is firmly tightened down and in place. Then install the fans and radiator as per your case compatibility:
 

 

 
You can see here that the radiator is as thick as a single SP120L so this entire assembly is only 75mm thick. You can also cut it down to 50mm total by using a single fan or go even lower by using slim profile fans if space is absolutely critical. But given the high fin density as well as the higher than average fin and tube thickness which all contribute to airflow restriction, I would suggest having at least a single 25mm thick fan on for decent performance.
 

 
You can then use the included PWM splitter to power and control both fans off a single header, preferably the CPU fan header since it is guaranteed to be a true PWM header. The pump itself is powered off a single 3 pin header (the cable is 12" long) and can be thus connected to any header which provided 12 volts. If hooked up to a DC header then you have the option of even voltage controlling the pump should you so desire.
 
Here's a look at the TIM spread from the pre-applied TIM on this socket:
 

 
As you can see this is not great. Between this universal design and the single application, I did all my testing with Gelid GC-Extreme so as to be able to get statistical accuracy and be able to do a lot of different tests as well. Keep this in mind during the thermal performance test section.
 
Now for LGA 115x:
 

 

 
Use the provided backplate with the notches pushed in towards the center and press it down into the motherboard from the back so that the tabs protrude upwards from the other side:
 

 

 
Then use the LGA 115x posts (these go in either way) and screw them into the backplate:
 

 
Once this is done, follow the same steps as before:
 

 

 

 
Dustin from Corsair also has an installation guide here. Lastly, I will show pictorially what to do if the Intel bracket comes loose or if you need to put on the AMD one instead:
 

 

 
Choose the bracket you wish to use.
 

 
Notice the teeth protruding from the pump/block unit. You need to align the bracket to go in between these:
 

 

 

 
Then align the outer ring in between these teeth as well:
 

 

 
Now simply push in the 4 tabs on this outer ring through the metal bracket securing the two in place:
 

 

 
If you notice that the Corsair logo is not in the center anymore when installed, then simply rotate the outer ring accordingly. Now let's test out the cooler properly, beginning with the fans and pump.
 
INDIVIDUAL COMPONENT TESTING
 
Testing methodology
Testing of the fan(s) was done with the fan mounted on the H75 radiator in push and push-pull, with the fan(s) controlled using a dedicated fan controller (Aquacomputer Aquaero 6 XT) in PWM mode and using the provided splitter. The controller also enabled RPM readout. Linear airflow was measured using an Extech 45158 Thermo-Anemometer 6″ away from the fan such that it measured the airflow in feet per minute through the radiator. Fan noise was measured in an anechoic chamber of size 5′ x 8′ with ambient noise level ~19 dBA and a sound probe held 6″ away to measure the sound volume in dBA accordingly.
 
The pump was tested was done with the 3 pin pump cable attached to the Aquaero in power mode which also helped monitor the pump RPM. Pump noise was measured in an anechoic chamber of size 5′ x 8′ with ambient noise level ~19 dBA and a sound probe held 6″ away to measure the sound volume in dBA accordingly.
 
Results


You can see that the fans have a very good PWM response curve. The max RPM goes from 1989 at 100% PWM to 755 at 40%, and the response is mostly linear. As far as noise goes, these fans are on the louder side with a single fan reaching ~54 dBA and both together getting close to 60 dBA. But the increase in airflow with both fans on is more than the increase in noise from both fans on, and that shows the radiator benefits well from push-pull. You can also slow both fans down to reach the same level of airflow as from a single fan but at a lower noise level. Alternatively, you can also replace the fan(s) with others that go better from a performance/noise ratio. I have tested out several fans already and will put these to the same standard test soon to see what other fans can work as alternatives. 3 fans which I actually know work better are the EK Vardar F3 and F4, and the Gentle Typhoon AP-45.
 
As far as the pump goes:

Without being able to measure the coolant flow rate, I can only provide the RPM and noise levels at various DC voltages. Undervolting the pump is not recommended by Corsair, but they have also said that people have ran these pumps at ~9-10 V with minimal performance issues. You do see a big drop in noise levels from 12 V to 9 V or so, but do note that in the end the pump is a lot quieter than the fans. So I would much rather you run the fans slower or replace them entirely than undervolt the pump. The pump went from 1501 RPM at 12 V (100% power on the 12 V rail) to 373 RPM at 3 V (25% power). But again, without knowing the exact flowrate I would not be able to suggest sticking past a certain number to guarantee turbulent flow in the radiator. Now let's see how these come together and perform thermally.
 
THERMAL PERFORMANCE
 
To find out how this performs as a cooler, I did thermal tests on 3 systems:
 
8 core: Intel i7 5960x (4.2 GHz at 1.2 Vcore) with quad channel DDR4 memory
(a) Fans and pump at 50% (Test 1)
( b )Fans and pump at 100% (Test 2)
 
4 core: Intel i7 4770k (4.5 GHz at 1.25 Vcore) with dual channel DDR3 memory
(a) Fans and pump at 50% (Test 3)
( b ) Fans and pump at 100% (Test 4)
 
2 core: Intel Pentium G3258 (4.5 Ghz at 1.2 Vcore) with dual channel DDR3 memory
(a) Fans and pump at 50% (Test 5)
( b ) Fans and pump at 100% (Test 6)
 
Each test was done in a climate controlled hotbox at 25 ºC ambient but the results will still be reported in terms of a delta T (component – ambient) in ºC. The ambient temperature should be nearly the same throughout the box with a +/- 0.25 ºC variability at most but still the ambient temperature sensor was held in front of the intake fan as should be the case with CPU coolers in my opinion. Each test/scenario was repeated three times and the average value taken to account of possible issues with mounting and TIM. Speaking of TIM, Gelid GC-Extreme was used as explained earlier and cure time was accounted for by measuring values after steady state was achieved post burning in with an Intel XTU run. Realtemp was used to measure the core temperatures.

These are pretty good temps, and with the fans/pump at 50% the sound level was not bad at all (32 dBA). In fact, you could also keep the pump at 100%, the fans at 50% and gain an extra 0.2 ºC improvement of temps on average showing that the fans end up contributing a lot more here. There are several factors you can also play around with- single fan, different fans, different TIM to name a few. Since I can't possibly account for all of these, I can only point you to the other component reviews that keep coming up here so you can then compare the different components and also point you to the fan testing plots on the previous page to see how these particular fans fared in push vs push-pull.
 
In order to compare the cooler with others, this is the scenario I chose: Intel i7 4770k at 4.5 Ghz, 1.25 Vcore, and everything set to full speed. I am not going to have any common components fans. My reasoning for this is that this is a test of the cooler unit and not just the heatsink or radiator. I will, however, use Gelid GC-Extreme for all the comparison tests because some coolers (such as this very one) don’t come with a tube of TIM for multiple usages and so a stock TIM there is moot anyway. So in this case, the H75 was tested with both the fans and pump at 100% (test 4 above):

As always, do look up the reviews of each of these other coolers to see how those coolers fared with different sockets and what contributed to noise and temperatures. The Corsair H75 with the fans in push-pull and pump all at 100% hangs in there with the bigger boys, and comes in cooler than the newer NZXT Kraken x41 which is a 140mm unit. But note that the Kraken (heh) ships with only a single fan. This is reflected in the higher noise level of the H75 as well. The massive Phanteks PH-TC14PE comes in quieter and cooler but it did have its own set of challenges too- especially making sure that the cooler inlet temperature is close to the ambient temps. This then is a function of the case and case airflow as well, but it is a lot easier to consistently handle liquid coolers with the radiator fans getting fresh intake than an air cooler that can perform terribly if the build is not planned out well. The Swiftech H220-X is pretty much a custom loop for all intents and purposes and is also priced higher, but does perform the best so far.
 
CONCLUSION
 
The Corsair Hydro H75 has an MSRP of $85 in the USA as of the date of this article. Thankfully the retail prices are lower, and the cooler can be found for $70 on Amazon and Newegg- again as of the date of this article. At this price, it comes up against the Phanteks cooler which, as we saw, is quieter and cooler. But don't be fooled- that is a massive dual tower air cooler and is definitely less compatible in most cases relative to this. It also has its own RAM height challenges as well. On the other side, due to the two included fans, it does outperform the larger/newer NZXT Kraken x41 but at a cost of higher noise. The H75 would really would benefit from better fans, which would not only cool more but also be quieter.  The pre-installed TIM on these AIOs is always a negative point in my books because of the single application but as I pointed out before- the TIM used here is a high quality, high price one. I would have liked to see the color accent rings included with the cooler. But overall, for a low profile AIO the Hydro H75 hangs well with the big boys and does not break your budget so I would recommend this to people. Be on the lookout for another article soon to see how this handles GPUs as well. Thanks for reading!