Low profile heatsink = high temp? Testing top-flow Noctua coolers

Conclusion and rating

Current PC hardware is already very energy efficient. Each new generation usually promises higher performance, lower power draw with corresponding cooling requirements. This trend is leading to the growing popularity of compact PC builds. However, these rigs face little space for coolers. How big trade-offs need to be made with CPU cooling in these builds? Does a small cooler necessarily mean high temperatures and noise?

Small but handy

Very popular SFF cases today include, for example, the Ncase M1 Mark VI or the Louqe Ghost S1 Mark III. Personally, I’m also quite looking forward to the Cooler Master NR200 which I’m planning for my next build with water cooling. But back to the Louqe Ghost S1 which I consider to be a very attractive SFF case and which I am only discouraged from acquiring by the extremely high purchase price. This case perfectly fits older Noctua NH-L12. However, this cooler is difficult to find today because it has been replaced by the newer NH-L12S. But it will not fit into the Louqe Ghost S1, because it is 4 millimeters higher than its predecessor. Recently, the renewed version of the NH-L12 with the nickname Ghost S1 Edition was released. I also requested the current NH-L12S model for this cooler and added NH-C14S to this pair. I used the NH-C14 for some time in the Streacom DA2 case, where it fit almost perfectly (after a minor modification with a Dremel milling machine). The trio of Noctua coolers, starring namely NH-C14S, NH-L12S and NH-L12 Ghost S1 Edition, will be introduced today.

As you can see from the table and from the photos below, the NH-C14S is not such a low cooler. It can be described as low-profile only with one eye shut. However, if its fan is placed under the heatsink, its total height is 115 millimeters. It is therefore still significantly lower than most conventional tower coolers. Nevertheless, its overall dimensions are not negligible and should be taken into account when choosing a suitable combination of cooler and case.

However, the two remaining coolers next to the NH-C14S look like dwarfs. The NH-L12S cooler together with the NH-L12 Ghost S1 Edition are very similar in size. But while the NH-L12 Ghost S1 Edition does not have a problem using RAM up to 48 millimeters high, the NH-L12S is limited to 35 millimeters. That is, if you place the fan under the heatsink. This is also the reason why the NH-L12S is overall a tad higher than the previous NH-L12 version. The culprit is a 120 mm fan that is already interfering with the DIMM slots next to the processor socket. Despite the small height of the NF-A12x15 fan used (fifteen millimeters instead of the usual twenty-five), the fan still almost touched the low Corsair LPX memory sticks in the test machine. Out of curiosity, I also wanted to try the NH-L12 cooler with the NF-A12x15 fan. Unfortunately, this fan could not be attached to the heatsink. The fins on the NH-L12 have a slightly different shape of the edges and the clips from the L12S cooler did not fit there. In addition, the entire heatsink did not even fit on the motherboard because the fan collided with the RAM modules. The clamping mechanism also differs, the NH-L12S (pictured below right) uses a newer type of spring screws.

I’m a little disappointed that the NH-L12 Ghost S1 Edition doesn’t use the more modern NF-A9 PWM fan instead of the used NF-B9 PWM. The NF-A9 PWM variant offers a higher value of maximum speed, which of course also offers a better air flow and significantly higher static pressure. It is also equipped with more modern SSO2 bearings and also has an improved frame design with anti-vibration pads. Every detail can play a role in such a small heatsink. As a consolation, you will find a higher-quality NT-H2 thermal paste in the packaging of this cooler, which I would personally like to see with every newly released Noctua cooler.

The packaging of all coolers is practically identical to all other Noctua coolers. That is, the SecuFirm2 mounting kit for attaching coolers to all current sockets (except Threadripper). Attaching the cooler to the processor is a piece of cake with this set, and I can hardly imagine any dramatic improvements. You will also find a low-noise adapter, and the NH-C14S also has a splitter cable for two fans. Furthermore, a typical screwdriver, a tube of thermal paste, clips for attaching fans (two sets for the NH-C14S), a metal sticker with the manufacturer’s logo and finally a user manual with clear installation instructions.

Current PC hardware is already very energy efficient. Each new generation usually promises higher performance, lower power draw with corresponding cooling requirements. This trend is leading to the growing popularity of compact PC builds. However, these rigs face little space for coolers. How big trade-offs need to be made with CPU cooling in these builds? Does a small cooler necessarily mean high temperatures and noise?

Testing methodology

Intel Core i7-5820K in ASRock X99 Taichi motherboard was used as the heat generator. As usual, I placed the whole build on the Streacom BC1 frame without other fans that would provide airflow. For stress tests, I used the Aida64 Extreme application with a duration of 45–60 minutes. The coolers were tested at three speed levels (800, 1200 and maximum) at a processor frequency of 4200 MHz and a voltage of 1.150 V. The processor power draw at these frequencies is around 150 W. I haven’t even tried to use the higher level that I usually use for other tests (4500 MHz with Vcore 1.350 V). The power draw of approx. 200 W is simply too high for this type of coolers.

To maintain the overall concept of the article, I tested all three coolers with fans in lower positions under the heatsink and with the air flow through the heatsink towards the socket. In addition, this configuration provides some airflow in the vicinity of the processor socket with a VRM, RAM, etc. For small cases, where airflow can be severely limited, this is a useful detail.

I measured the noise at three fan speed levels (800, 1200 and maximum) approx. 50 cm from the cooler using a calibrated Voltcraft SL-100 instrument in the fast measurement mode (125 ms) with a sensitivity range of 30–100 dBA. The fan speed was controlled by the Noctua NA-FC1 controller. The ambient noise level is usually around 33 dBA. At the end of the test, the highest temperature value reached by the entire processor was observed. All data regarding processor temperatures and energy consumption are obtained from the HWiNFO64 software. The results are then corrected for ambient temperature as the resulting Delta T. The test success limit is set at 80 °C. A higher Delta T value already means a processor temperature above 100 °C and a risk of thermal throttling. Therefore, if the cooler does not pass the test with a Delta T value below 80 °C, such a test is rated as failed.

Test results

It can already be seen here that a high amount of waste heat in combination with low speeds means that most coolers are not able to prevent the processor from overheating and subsequent throttling. This is not unexpected, it is simply the physical limit of the cooler and does not mean that the cooler is of poor quality.

Current PC hardware is already very energy efficient. Each new generation usually promises higher performance, lower power draw with corresponding cooling requirements. This trend is leading to the growing popularity of compact PC builds. However, these rigs face little space for coolers. How big trade-offs need to be made with CPU cooling in these builds? Does a small cooler necessarily mean high temperatures and noise?

Conclusion and rating

So what is the result of today’s triple test? That it is difficult to evaluate and compare specialized coolers designed for small cases. But I’ll follow the order. NH-C14S did not surprise me, but did not disappoint either. Given the size of its heatsink and the fan used, I would be struck if it could not reasonably and quietly cool the i7-5820K @ 4200 MHz used in the tests. However, it can be seen that a classic tower architecture is an overall more efficient cooler design. The results of the NH-C14S are very similar to those of the smaller, quieter and significantly cheaper Pure Rock 2 cooler from BeQuiet! Nowadays, a horizontally placed set of fins is rather a specialty these days, intended for smaller cases that do not have enough space for high tower coolers. The biggest negative of the NH-C14S is its higher price.

However, I was pleasantly surprised by the NH-L12S. I did not expect that such a small cooler will solidly cope with a stress test, for which it is not even technically built, as it exceeds its TDP rating by about 50%. But I was even more struck by the dramatic difference between the NH-L12S and the NH-L12 Ghost S1 Edition. The heatsinks of these coolers are very similar. The big difference, of course, is in the fan used. Even so, it struck me that the NH-L12 turned out so much worse. I decided to reassembly and test it again, but the result was the same as in the first test. We are talking about 15–20 °C higher temperatures which is really a big difference. Again, this is a stress test that exceeds by about 50% the TDP rating of the NH-L12 Ghost S1 Edition cooler. It can be expected that a compact case such as the Louqe Ghost S1 Mark III will be equipped with a less power-thirsty processor with a TDP of around 65 W and not an overclocked HEDT processor with high power draw.

The bottom line, however, is that the NH-L12 Ghost S1 Edition is a cooler suitable for virtually only one specific case. Anywhere else I will recommend the NH-L12S more, of course, if it fits the size of the case. All three coolers share a six-year warranty traditional for Noctua, excellent build quality, but unfortunately also a higher price tag.

English translation and edit by Lukáš Terényi

• Contents
• Key features
• Measuring methodology and tests results
• Conclusion and rating