While we couldn't take numerous detailed photos of nine different cooler installations and keep this article a manageable length, we're providing installation notes for each model below, along with one photo for each cooler. Feel free to click on any of the photos to get a full-size view.
The Stock Intel Cooler
This cooler really needs no introduction, except perhaps to folks who are actually buying Intel's latest generation of unlocked "-K" processors, which no longer include it. That's a shame, because it's a very good cooler for the price ($0). You might argue that the cooler wasn't free, in that the cost was included in the price of previous-gen Intel processors, but alas, given that current-gen -K processors are actually more expensive than their forebears, that argument really doesn't hold water. In reality, this is just a case of Intel trying to make a few more dollars on every CPU sale. It has nothing to do with the cooler's ability to function correctly on -K processors, nor with cost savings being passed onto consumers who would likely upgrade the cooler anyway.
All this is to say that our reference Intel cooler came from an Intel Core i7-4770K processor, not the Core i5-6600K we were testing with. And as with all of Intel's basic reference coolers over the years, this one uses plastic push-pins to attach to the motherboard. The more we use these, particularly in light of all the other mounting systems we've tested, the less we like them. The plastic push-pins may be attractive in the sense that they require no other hardware, nor access to the back of the motherboard, but they are actually harder to use than they should be, and often require a number of firm pushes to properly engage.
The one thing that the Intel cooler certainly has going for it is compatibility. Given that every motherboard and every case (save for a few ultra-thin models) is built around Intel's CPU socket specification, you really shouldn't have trouble fitting the Intel cooler in your system. There are no surprising overhangs nor challenging height issues to deal with. It just fits.
The NH-L9x65 uses Noctua's well-designed SecuFirm2 mounting system, which employs a backplate behind the motherboard to improve to reduce the chance of warping, while also making installation easier overall. You will need access to the back of the motherboard, but that's true of all but the Intel cooler in this roundup. The NH-L9x65 features captive spring-loaded screws attached to the heatsink, which connect to standoffs on either side of the motherboard. All told, this is a secure and safe method of attachment, with very little chance of bending the motherboard or CPU heat spreader due to over-tightening of the heatsink.
Noctua informed us prior to testing that a new version of the NH-L12 will be arriving sometime in the near future, and we're pretty sure the number one priority for that new model will be to get rid of the first-generation SecuFirm bracket, which has been copied by other manufacturers (most notably in this roundup the SilverStone with its NT06-Pro), but pales in comparison to the SecuFirm2's ease of use. You have to install each post individually through the backplate, and then hold them in place while attaching the standoffs on either side of the CPU. Adding to the complexity of the installation is the fact that you need to thread your screwdriver through several fan blades to secure the heatsink, unless of course you choose to remove the top fan during installation and then re-install it. At least the NH-L12 has captive spring-loaded screws and a fixed locking plate, meaning you don't need four hands to install it!
By the way, we should note that Noctua markets the NH-L12 as having two modes: dual-fan mode, and "low-profile" mode, which uses just the lower 92mm fan to achieve a height of 66mm. We chose to only test the cooler at full strength, as we don't think it would make sense to buy this model and not run it with the larger fan.
The Brontes turned out to be one of the easiest coolers to install. Using a simple attachment design (screws through the back of the motherboard attach to wings on the heatsink), this installed in just a few minutes. And due to the well-designed cutouts on the underside of the heatsink, the Brontes had no trouble with RAM clearance on either RAM kit we tried (ultra-low-profile as well as standard low-profile). Another bonus for ITX builders: the frame of the Brontes does not overhang the motherboard's perimeter, meaning you will not end up running into the side or top panel of your case with the Brontes.
The one thing we don't like about the mounting system used by the Brontes (as well as the Reeven Steropes and the SilverStone AR06) is the fact that you must hold the cooler in place with one hand while affixing the screws through the back of the motherboard with the other hand. If you don't have a magnetic screwdriver, this could virtually require that you have three hands!
When Reeven reached out to us about its low-profile coolers, we originally requested only the Brontes. We were pretty sure the Steropes would not fit on our ITX motherboard. Reeven, however, was insistent, and provided the Steropes along with its opinion that it would definitely fit.
Well, here's how that all played out: using our ultra-low-profile DDR4 kit, purchased specifically for testing low-profile coolers, the Steropes did indeed fit, with about 2mm to spare above our RAM's heatsinks. But using the most popular low-profile RAM design on the market, our Corsair Vengeance LPX, the Steropes simply could not be used. We went ahead and tested it with our ultra-low-profile kit, but it will not be receiving any awards, regardless of performance, because we consider it to be technically disqualified.
And that's not the Steropes only challenge. In fact, while it uses the same simple bracket design as the Brontes (screws go through the back of the motherboard, attaching to metal wings on the heatsink body), it presented a unique challenge. If your case doesn't have rear motherboard access, you simply cannot build your system properly. That's because once you've installed it, it blocks access to one of the four motherboard attachment points, leaving only three screws with which to secure the motherboard. While you can certainly operate a PC with that screw missing, we wouldn't recommend transporting it, especially with the significant weight of the Steropes hanging off of it, which is doubly-concerning given the lack of a backplate on this relatively-large cooler.
But we're not done yet: the Steropes overhung our motherboard's perimter by about half an inch, meaning that it will not fit in some cases even if there's enough clearance above the CPU. We'll have a bit more to say about the Steropes in our conclusion, as despite all of its challenges, we still appreciated what Reeven tried to do with the Steropes.
Well, this is going to end up being a short story. We were excited to try out the brand-new SilverStone NT08-115X for a number of reasons. First, it would be a great low-cost option for users of the Intel Core i5-6600K CPU that we used, as well as the Core i7-6700K, neither of which come with coolers, as discussed above. The cooler appears to fit in the exact same space as the stock Intel cooler, but features a larger fan and a bigger heatsink. It's also designed exclusively for the Intel 115X platform, making it all the more obvious that SilverStone really is targeting Intel's latest generation of CPUs. It cannot be used for AMD processors, nor for Intel's High-End Desktop processors (i.e., the six-core, eight-core, and ten-core models). Finally, it has an ultra-simple and sturdy mount design, featuring a metal bracket for the rear of the motherboard, and four pre-installed spring-loaded screws to attach the heatsink to the bracket.
Perfect, right? Not so fast. It looks like SilverStone may have rushed through the testing phase for this cooler in order to get it to market quickly. In short, it's completely incompatible with the ITX format, for one simple reason: the fan shroud's plastic retaining clips sit right above the RAM slots, as highlighted in the photo we've provided. While it seemed that the clips could be rotated somewhat to avoid the RAM slots, this would require disassembly of the cooler, which would likely void the warranty. In other words, this is where our testing of the NT08 ended. We couldn't secure the right side of the cooler, as the fan shroud was actually sitting right on top of one of our ultra-low-profile DDR4 RAM sticks.
We know SilverStone will be reading this article, and we hope they'll be able to remedy the flaw in the NT08's design before extensive retail shipments have begun. It holds a lot of promise for builders on a budget, and we truly wish we could have tested it against the reference Intel cooler.
Luckily, SilverStone redeems itself with its excellent AR06 cooler. Featuring a simple but effective mounting system that takes all of five minutes to install, the AR06 is a pleasure to work with... as long as you have access to the rear of your motherboard. While no bracket is required, you actually have to affix the mounting screws through the back of the motherboard, into the AR06's metal "wings." While attaching large coolers without a rear-mounted backplate is asking for serious trouble (in the form of a warped motherboard), due to the lightweight nature of the AR06, that's really not an issue here. But as with the Reeven twins, which use a nearly identical system, you practically need three hands to hold the cooler in place on one side of the board, while affixing the screws through the other side.
There is one potential pitfall in the AR06's design in terms of clearance, and that is the four heatpipes, which protrude 1.3cm (about half an inch) out of the AR06's heatsink. While it wasn't an issue in our installation, there are some motherboards that may have cable headers or chipset heatsinks in the vicinity of these heatpipes, so if you'll be using this cooler on an ITX board, make sure you scope out where these motherboard components could potentially interfere with the AR06's heatpipes. We know, for example, that the AR06 will prevent the attachment of the USB 3.0 cable on Gigabyte's line of Socket 1151-based ITX motherboards, including its GA-Z170N-WIFI and GA-Z170N-Gaming 5 models. On these boards, the AR06 will have to be oriented in the opposite direction if the USB 3.0 header is to be used.
Time to be blunt: the NT06-Pro was an absolute pain to install, in fact offering up the most difficult installation process of any cooler we've ever tested. It's just begging for a redesign, and in fact, we're guessing it was never really designed to be installed with a fan at all. You see, the NT06-Pro began its life as the passive NT06, which used its excellent heatsink design to run on systems without the use of a cooling fan. That made it relatively easy to install, because you could slip your hand underneath and position its unusual floating bracket, while affixing it through the heatsink using a screwdriver. Well, with the NT06-Pro, that's simply not possible, unless you install it in a case that affords you the luxury of clipping the fan on after you've attached the heatsink. And while our ATX case with a removable top would have allowed this, we weren't going to bend the rules for the NT06-Pro, as few ITX cases would allow such access. And getting that floating bracket lined up underneath the fan without being able to actually see it or hold it, while affixing the two spring-loaded screws, literally took us about 25 minutes.
Making matters worse was the fact that the NT06-Pro's size meant that the CPU fan header and CPU power header were blocked once the cooler was in place, a problem we didn't catch on to until after we'd affixed the cooler. So we had to go through the arduous process of screwing in that bracket twice. Not fun. For all these reasons, the NT06-Pro is never going to be our favorite cooler. And with just a few millimeters of clearance above our Corsair Vengeance LPX RAM, it narrowly avoided being disqualified for clearance. We had high hopes for its performance, though, and as you'll see on the following pages, it did avail itself fairly well, except in one critical aspect of performance...
Thermalright AXP-100 uses an annoying floating bracket, similar to the SilverStone NT06-Pro, but because the heatsink is a lot smaller, it's not quite as much of a pain to install. But it's not great, and there's no other way to put this: the AXP-100 took by far the longest to install of all the compact coolers due to the huge assortment of spacers, screws, brackets, and nuts required to affix it. Our hunch is that Thermalright could greatly simplify the installation procedure if it weren't using a mounting system originally designed for its much larger tower-style coolers.
And then there's the matter of clearance. As it turns out, the Muscle fails here, as it actually couldn't even clear our ultra-low-profile RAM sticks. While we were able to get it to fit, the heatsink pushed against the left RAM stick, causing it lean over by a millimeter or so while putting extreme pressure on our motherboard's first RAM slot. And this renders the AXP-100 technically disqualified from winning an award, regardless of its performance. We would never recommend that builders use it with our test configuration. Yes, we tried orienting it in other directions, but no matter what, it hit some component on our motherboard, whether it was the PCIe slot, the WiFi module, or the upper heatsink.
One bit of good news: the white-on-black color scheme of the Muscle's fan will likely go with plenty of builds, unlike the beige, yellow, and blue of its competitors!
The coolers we tested really fall into two categories when it comes to installation: those that conform to the Intel "keepout" area measuring 95mm x 95mm, and those that do not. Only the Intel heatsink, the Noctua NH-L9x65, and the SilverStone AR06 fall into the former cateogory, and the AR06 in fact cheats a bit with its protruding heatpipes. All the other heatsinks are larger in terms of their perimeter, which may cause challenges with certain motherboards. Most builders probably know to check the CPU height clearance for their cases, as this is an advertised specification on all new case models (at least those that are worth considering, that is), but width and length are impossible to plan around, as you can't get a specification of a motherboard's clearance, nor a case's tolerance for coolers that extend beyond the motherboard's perimeter. In other words, picking coolers for small form factor PCs is tricky. We've tried to do our best here to point out the pitfalls, but given that mini-ITX motherboards can use very different layouts, we'll have to leave it up to our readers to determine whether a particular cooler will work with their unique combination of components. Another important note: coolers that use heatpipes should be oriented with the heatpipes facing down, if possible. With our Thermalright cooler above, we weren't able to fit it that way, but you'll note that with every other cooler that features an array of heatpipes, the heatpipes were indeed facing down.
For those keeping score, three of our nine contenders have already been disqualified: the SilverStone NT08-115X, which could not be installed at all, the Thermalright AXP-100 Muscle, which pressed heavily against one of our ultra-low-profile RAM sticks, and the Reeven Steropes, which failed the compatibility test with our standard Corsair Vengeance LPX RAM. Of these three, only the NT08-115X's issues were so serious that they'll keep it from appearing in the charts that follow on the next few pages.
All right, it's time to look at some benchmarks!