A standard cooler is supplied with nearly all retail boxed CPUs, which guarantees adequate cooling performance under normal operating conditions. Enthusiasts however are rarely satisfied with the performance of stock CPU coolers, seeking either better overall performance or lower noise levels. This is especially true for those who are planning to overclock their systems, as the supplied coolers usually don't have the extra performance required for handling overdriven processors.

However, the selection of a CPU cooler is a complicated matter. It depends on the available space, the user’s needs and wants, as well as on the available budget. For example, some users might require high performance but low profile coolers due to limited space, while others may have spacious cases and high enough budgets to afford a huge dual-tower cooler.

In today's review we will be having a look at some of the most popular single tower 140 mm CPU coolers currently available. Considering that height usually is the primary concern with CPU coolers, single tower 140 mm coolers virtually have the same space requirements as the dual tower 140 mm coolers do. Their distinct advantages however are much lower weight and significantly more competitive pricing. This makes them ideal for users that do have the available space, but do not require the performance of a dual-tower behemoth or move their system often, in which case the cooler’s weight becomes a major safety concern.

Thermalright True 140 Direct, Phanteks PH-TC14S, Be Quiet! Shadow Rock Slim, & Noctua NH-U14S

The four coolers that we are taking a look at in this roundup review are the: Noctua NH-U14S, Phanteks PH-TC14S, Thermalright True Spirit 140 Direct, and the Be Quiet! Shadow Rock Slim. All four of these coolers have similar space requirements and pricing, but they are certainly not created equal. We will have a closer look at their individual strengths and weaknesses in the following pages of this review.

140mm Tower CPU Coolers
Product	Fan(s)	Fan Speed (RPM)	Height (mm/in)	Current Retail Pricing
Noctua NH-U14S	1 × 140 mm	1500 RPM	165 mm / 6.5”	$65
Phanteks PH-TC14S	1 × 140 mm	1300 RPM	160 mm / 6.3”	$50
ThermalRight True Spirit 140 Direct	1 × 140 mm	1600 RPM	161 mm / 6.34”	$47
Be Quiet! Shadow Rock Slim	1 × 140 mm	1400 RPM	161 mm / 6.34”	$50

Noctua NH-U14S 

Starting things off, we have the Noctua NH-U14S. Noctua supplies the NH-U14S inside a large, sturdy cardboard box. The artwork on the box is austere, limited to providing useful information about the cooler itself.

Inside the box everything is individually packed into separate cardboard boxes. Alongside with the mounting hardware, Noctua is also offering a basic screwdriver for the installation of the cooler, a fan speed reducer, a metallic case badge and a syringe with NT-H1 thermal compound.

Noctua offers a very large selection of CPU coolers, with at least one product per cooler type. The NH-U14S is their version of a single tower cooler that makes use of a 140 mm fan and, according to Noctua, it has been designed so as to offer the best possible overall performance while staying clear of the LGA2011/LGA2066 RAM slots. It also is slightly taller than the other coolers of this review, even if only by 4-5 mm (0.15”-0.2”).

The company characterizes the NH-U14S as a “slim” cooler, but the dense fin array is 52 mm deep and 150 mm wide, providing more than ample heat dissipation surface. In theory, the cooler should be able to handle thermal loads well above 200 Watts. The top fin of the array is not thicker but has the company’s logo and name engraved on it.

The NH-U14S makes use of six thick heatpipes to transfer the heat from the base of the cooler to its fin array. Each heatpipe expands to either side of the fin array and the designers had each heatpipe expanding at a different distance from the center of the fin array, resulting to twelve evenly distributed thermal energy transfer lanes from the base of the cooler to fin array. The heatpipes are made of copper but are nickel plated. The joints are all soldered, ensuring maximum thermal transfer and mechanical cohesion.

Only the bottom part of the cooler’s base that makes contact with the processor is made out of copper. The top half of the base is made out of aluminum and the mounting bracket is nickel-plated steel. As only the bottom part actually contributes on the transfer of the thermal energy from the CPU to the heatpipes, this is a very reasonable design for the reduction of a cooler’s weight and overall cost. A full copper base would substantially increase the weight of the design without offering any advantage.

The copper base of the NH-U14S has also been nickel plated and is very smooth, yet not machined down to a perfect mirror finish. It appears to be easy to clean and difficult to soil. Noctua generally does not polish the bases of their coolers as it makes no apparent difference on performance, so they opt to not raise the cost of their products even higher for something that would not make an actual difference. 

Phanteks PH-TC14S

Phanteks supplies the PH-TC14S inside a dark cardboard box with an abstract aesthetic theme, mostly based on schematic drawings of the cooler itself. It is not a very large box for a cooler that size, but it is very sturdy and the cooler is protected with polystyrene foam packaging, making it nearly impossible to damage during transport.

Inside the box we found four manuals, one for each of the most popular languages in the regions that the cooler is being marketed into, the necessary mounting hardware and a syringe with Phanteks PH-NDC thermal compound that should last for at least a couple of applications.

The Phanteks PH-TC14S is the “cheater” of this review, as it is not a single tower but a dual tower cooler design. It technically is a baby version of the monstrous PH-TC14PE that we had a look at a couple of years back. Still, this is Phanteks' only slim 140 mm tower cooler offering, and it is of comparable size to every other cooler in this roundup review. What the designers of Phanteks did was to split the single tower array into two very narrow arrays and place the 140 mm fan in between them. Strangely, the fins are significantly smaller than the fan without any apparent reason, meaning that there will be a significant loss of airflow to every direction.

The array fins are very thin and not strong individually, but they are soldered on the thick heatpipes that are only a few millimeters apart from each other. One major feature of the PH-TC14S is its black fins. Phanteks calls this paint job "Physical Antioxidant Thermal Shield" (or Physical Antioxidant Thermal Spraying - we found both in the company's texts) and claims that it enhances thermal performance by both increasing the dissipation rate of the heatsink itself and decreasing the radiation absorption rate from other heat sources. Unlike the PH-TC14PE, the PH-TC14S is available only in black.

The PH-F140HP fan also is a primary marketing focus of this product. It has the lowest RPM rating of every fan in this review (1300 RPM) but impressively high static pressure specifications (1.64 mm H₂O at max speed).

Six thick heatpipes expand to either side of the small base. With the fin arrays placed in parallel, each heatpipe enters both arrays. Although that design appears very symmetric and effective at first, it actually does not appear to be optimal, as the two middle heatpipes that will be right above the CPU core and will be facing the bulk of the heat transfer enter near the fin arrays near the middle, where the fan’s airflow will be the lowest due to the dead spot under its motor.

The rectangular copper base of the PH-TC14S and the copper heatpipes are all nickel plated. Like with the majority of modern coolers, the base of the PH-TC14S is made of two parts, a copper contact plate and an aluminum top frame. The lower half of the base handles the thermal energy transfer away from the CPU and to the heatpipes, while the top half only offers mechanical cohesion and support for the steel mounting brackets. The nickel plated base is very smooth and machined down to a near-perfect mirror finish.

Be Quiet! Shadow Rock Slim

Be Quiet supplies their tower cooler in a black, sturdy cardboard box, with minimal artwork but plenty of information about the cooler printed on all sides of the box. The company straightforwardly advertises that this cooler is capable of handling CPUs with thermal design power (TDP) up to 160 Watts, but this figure alone does not tell much about the overall performance of a cooler.

Inside the box we found a frugal bundle, consisting of a one-fits-all backplate, mounting hardware, a syringe with thermal compound, and a leaflet with very basic installation instructions.

The Shadow Rock Slim initially appears to be a very simple tower cooler that has been designed for 140 mm cooling fans. A closer inspection however reveals a very complex fin cutout that has been developed so as to minimize aerodynamic drag and, in extend, the noise that is being created by the moving airflow. A thicker, decorative metallic plate with the company logo etched on it can be seen at the top of the fin array. Rounded metallic caps cover the heatpipe end points.

Despite its “slim” identification, the Shadow Rock Slim is not really a slim CPU cooler. It certainly is much smaller than the monstrous Dark Rock Pro 3 that we reviewed a couple of years back, but still the body of the cooler alone is 52 mm wide. It comes with one of the company’s better fans, a special 135 mm variation of their “SilentWings” series. These fans feature a rifle bearing engine, which greatly improves the lifetime of the fan relative to the typical sleeve bearings, all the while retaining similar low-noise operation characteristics.

The Shadow Rock Slim is designed with only four heatpipes and a slightly smaller base than that of the other coolers in this review. Its design is sound, with the two middle heatpipes that will be facing the bulk of the thermal energy flow expanding into the edges of the fin array, where the airflow is going to be greater. This is the only cooler of this review that does not have nickel-plated heatpipes, so we can expect that their vibrant polish will soon disappear due to oxidation. (Oxidation doesn't cause any real damage, but it does eventually affect the cooler’s aesthetics)

The lower half of the cooler’s base is also made out of copper but, unlike the heatpipes, it is nickel plated. It has also been polished down to an immaculate mirror finish. The top half of the base is solid aluminum and does look like a small heatsink, yet its contribution to the overall performance of the cooler will be negligible, it is only meant to provide mechanical cohesion and support for the mounting hardware.

Thermalright True Spirit 140 Direct

Thermalright is practically a newcomer here in AnandTech, as we have not looked at any of their products since 2010 and our last Thermalright CPU cooler review is now nearly a decade old. The cooler that we will be reviewing today is the Thermalright True Spirit 140 Direct, the upgraded version of their popular Thermalright True Spirit 140 cooler. It comes supplied inside a dark box with minimal artwork, only a clear picture of the cooler itself and icon denoting its most important features.

Inside the box we only found the absolute necessary parts for the installation of the cooler, which are a one-fits-all backplate, mounting hardware, fan support wires, fan anti-vibration standoffs, and a small but detailed installation manual. Thermalright also supplies one dose of their “Chill Factor” thermal compound.

Much like Noctua’s and Be Quiet!’s offerings, the Thermalright True Spirit 140 Direct has a single 52 mm deep fin array with a 140 mm fan attached on it. The fin array is relatively simple, with only a recessed center area to reduce the aerodynamic drag noise. The top fin of the array has been painted black for aesthetic purposes. It has five 6 mm nickel-plated heatpipes.

Thermalright is using one of their TY-140 cooling fans on the True Spirit 140 Direct. The TY-140 is a PWM general purpose cooling fan that has been initially designed with 120 mm mounting holes to maximize compatibility. The company advertises its “Enhanced Hyper-Flow Bearing (EHFB)” engine as consistent and highly reliable, without any further information regarding its design and/or mechanics.

The fan mounting mechanism is strange, with the fan having to sit on rubber standoffs that need to be inserted into small cutouts on the fin array. It is not possible to mount the fan without these standoffs. Hopefully the rubber that they are made of will last for several years, but replacements may be necessary for people who keep their hardware for more than a few years or if they are lost. (Tip: Pieces of large drinking straws do work as a temporary solution)

The large difference between this cooler than the others in this roundup review (and also its major upgrade over the previous version) is the design of its base. Instead of having a contact plate coming in contact with the CPU and the heatpipes attached to it, the heatpipes of the True Spirit 140 Direct are in direct contact with the CPU itself. The top part of the base is made of machined aluminum and only provides mechanical cohesion and retention bracket support.

Testing Methodology

Although the testing of a cooler appears to be a simple task, that could not be much further from the truth. Proper thermal testing cannot be performed with a cooler mounted on a single chip, and this is for multiple reasons. This includes the instability of the thermal load and the inability to fully control and or monitor it, as well as the inaccuracy of the chip-integrated sensors. It is also impossible to compare results taken on different chips, let alone entirely different systems, which is a great problem when testing computer coolers, as the hardware changes every several months. Finally, testing a cooler on a typical system prevents the tester from assessing the most vital characteristic of a cooler, its absolute thermal resistance.

The absolute thermal resistance defines the absolute performance of a heatsink by indicating the temperature rise per unit of power, in our case in degrees Celsius per Watt (°C/W). In layman's terms, if the thermal resistance of a heatsink is known, the user can assess the highest possible temperature rise of a chip over ambient by simply multiplying the maximum thermal design power (TDP) rating of the chip with it. Extracting the absolute thermal resistance of a cooler however is no simple task, as the load has to be perfectly even, steady and variable, as the thermal resistance also varies depending on the magnitude of the thermal load. Therefore, even if it would be possible to assess the thermal resistance of a cooler while it is mounted on a working chip, it would not suffice, as a large change of the thermal load can yield much different results.

Appropriate thermal testing requires the creation of a proper testing station and the use of laboratory-grade equipment. Therefore, we created a thermal testing platform with a fully controllable thermal energy source that may be used to test any kind of cooler, regardless of its design and or compatibility. The thermal cartridge inside the core of our testing station can have its power adjusted between 60 W and 340 W, in 2 W increments (and it never throttles). Furthermore, monitoring and logging of the testing process via software minimizes the possibility of human errors during testing. A multifunction data acquisition module (DAQ) is responsible for the automatic or the manual control of the testing equipment, the acquisition of the ambient and the in-core temperatures via PT100 sensors, the logging of the test results and the mathematical extraction of performance figures.

Finally, as noise measurements are a bit tricky, their measurement is being performed manually. Fans can have significant variations in speed from their rated values, thus their actual speed during the thermal testing is being acquired via a laser tachometer. The fans (and pumps, when applicable) are being powered via an adjustable, fanless desktop DC power supply and noise measurements are being taken 1 meter away from the cooler, in a straight line ahead from its fan engine. At this point we should also note that the Decibel scale is logarithmic, which means that roughly every 3 dB(A) the sound pressure doubles. Therefore, the difference of sound pressure between 30 dB(A) and 60 dB(A) is not "twice as much" but nearly a thousand times greater. The table below should help you cross-reference our test results with real-life situations.

The noise floor of our recording equipment is 30.2-30.4 dB(A), which represents a medium-sized room without any active noise sources. All of our acoustic testing takes place during night hours, minimizing the possibility of external disruptions.

<35dB(A)	Virtually inaudible
35-38dB(A)	Very quiet (whisper-slight humming)
38-40dB(A)	Quiet (relatively comfortable - humming)
40-44dB(A)	Normal (humming noise, above comfortable for a large % of users)
44-47dB(A)*	Loud* (strong aerodynamic noise)
47-50dB(A)	Very loud (strong whining noise)
50-54dB(A)	Extremely loud (painfully distracting for the vast majority of users)
>54dB(A)	Intolerable for home/office use, special applications only.

*noise levels above this are not suggested for daily use

Testing Results: Maximum Fan Speed

To start things off, let's take a look at the peak cooling performance of our four tower coolers. We should note that the Phanteks PH-TC14S is once again the oddity of this review, with its fan reaching 1520 RPM. The specifications of the PH-F140HP fan state a very broad maximum speed range of 1300 ± 250 RPM, so our reading is within the fan’s specifications, yet this is the first time that we have encountered a fan spinning that much faster than its rated speed.

With their fans running at their maximum speed, the best overall thermal performance comes from Thermalright’s True Spirit 140 Direct. Noctua’s NH-U14S handles high loads a little better, but Thermalright’s offering has a very strong advantage at lower loads, suggesting more efficient heat transfer due to its direct contact design. 

The Be Quiet! Shadow Rock Slim falls a little behind in terms of thermal performance but only by a couple of degrees, which is acceptable considering that it had the lowest noise reading of this review. Considering the overall design of the cooler and that it has a smaller number of heatpipes in comparison to every other cooler in this review, its top speed performance is surprisingly good.

Core Temperature, Constant Thermal Load (Max Fan Speed)

60 W Load100 W Load150 W Load200 W Load250 W Load340 W Load

Although its thermal performance is satisfactory, the Phanteks PH-TC14S falls behind the other three coolers of this review. It is both slightly louder and less efficient, especially when it has to deal with very high thermal loads. The difference however is small and a more carefully designed revision can easily turn the tables.

Testing Results: Low Fan Speed

As most users don't actually need the fans of a tower cooler running at peak performance (and peak noise), let's also take a look at what kind of performance these coolers provide at lower fan speeds.

Broadly speaking, all four of the coolers that we tested for this review were capable of sustaining reasonable operating temperatures with thermal loads above 200 Watts, even with the speed of their fans greatly reduced.

There are virtually no differences between these four coolers in relation to our previous test, with the Thermalright True Spirit 140 Direct again displaying the best overall thermal resistance and excellent efficiency with the handling of low thermal loads. However, the Noctua NH-U14S greatly outperforms all other coolers when it comes to the handling of very high thermal loads, suggesting that it can maintain reasonable operating temperatures on overclocked processors alongside with virtually inaudible noise levels.

Once again, the Be Quiet! Shadow Rock Slim falls slightly behind the Noctua NH-U14S and the Thermalright True Spirit 140 Direct. The thermal resistance is only slightly worse but this time the Shadow Rock Slim also has no real advantage in terms of acoustics, as the difference between all four of the coolers is practically indiscernible.

Core Temperature, Constant Thermal Load (Low Fan Speed)

60 W Load100 W Load150 W Load200 W Load250 W Load340 W Load

Finally, the Phanteks PH-TC14S displayed the lowest overall performance figures, with slightly worse thermal resistance than all of the coolers in this roundup review. Although the Phanteks PH-TC14S displays thermal performance similar to that of the other coolers at lower loads, the difference widens greatly when the thermal load is very high, suggesting that the cooler is at its limit in handling the excessive thermal energy flow.

Final Words

Although 140 mm tower coolers are slightly restrictive in their compatibility – essentially requiring the user to own a case that is wide enough to fit them – their close pricing and superior characteristics relative to 120 mm tower coolers makes them the sensible choice for every enthusiast that owns a compatible case. The four coolers in this review are but a small sample of the “slim” 140 mm coolers available today, comprising of the higher quality and most popular models.

Out of these four coolers, Noctua’s NH-U14S stands out by pretty much every metric. It is a little larger than the other three coolers and, even though the difference is small, extra caution is required when checking whether it can fit inside a case. At $65 it's also more expensive than the other three models by around 30% ($15), which makes it substantially more expensive. Nevertheless, the thermal performance of the NH-U14S is significantly superior as well, especially when the cooler needs to handle a high thermal load. This higher thermal performance coupled with Noctua's excellent reputation for their after-sales support gives the NH-U14S an edge over its competition, regardless of its higher retail price.

The Phanteks PH-TC14S was the oddity of this review. Instead of doing a single tower cooler, the designer’s solution for a “slim” design was a greatly cropped version of the monstrous PH-TC14PE. The narrow and thin towers hardly cover the effective airflow area of the 140 mm fan that is sandwiched between them, and the positions of the heatpipes do not appear to be optimal. Still, the PH-TC14S performs very well overall, better than what we originally anticipated when we physically examined the cooler. The lack of mass places it at a disadvantage when it needs to deal with very high thermal loads, but it will be more than sufficient for the average gamer and amateur overclocker. It also is the only cooler that is currently available with black fins, drawing the attention of those who prioritize aesthetics over small performance differences.

Thermalright’s True Spirit 140 Direct was the surprise performance of this roundup review. Nothing foretold that the otherwise simple-looking cooler could give the competition such a push. The direct contact design of the True Spirit 140 Direct grants the cooler excellent energy absorption efficiency, giving the cooler a significant performance advantage that is especially apparent when the thermal load is low. This design makes the True Spirit 140 Direct particularly efficient when dealing with low thermal loads, i.e. modern efficient CPUs that will not be significantly overclocked. It is not as efficient when it has to deal with a very high thermal load, as it cannot dissipate the amassing thermal energy as quickly as Noctua’s behemoth can, but even then the performance figures remain very good. Its sound pressure levels are relatively low as well, making it a sensible choice for users who want a relatively simple, efficient, low noise product.

Finally, the Be Quiet! Shadow Rock Slim is not the best overall performer of this roundup review, but we feel that it is right where the company wanted it to be. Its thermal performance is competitive, rivaling that of every other cooler in this roundup, and even coming close to its much larger and considerably more expensive counterpart, the Dark Rock Pro 3. At the same time, the sound pressure level readings of the Shadow Rock Slim are the lowest of this review, even if only by a little, making it the quietest of the coolers. Overall, the Shadow Rock Slim is a balanced, high quality cooler that should appeal to the widest user’s base in comparison to the other coolers of this review. If the company were to bring the price of the cooler down even just a bit, then the competition would have a lot to worry about.