by Sergey Lepilov
05/03/2009 | 03:44 PM
Worldwide economic crisis didn’t affect each and every branch of the economy. At least, the development and manufacturing of air-coolers for system CPUs and graphics cards doesn’t seem to have been affected: there is no stagnation, no slowing down of the production or bankruptcy announcements. Moreover, new cooling solutions keep coming out just the way they used to: one after another. The remarkable thing about it is that the new coolers more often turn out inferior to the already existing models in cooling efficiency, noise and price, than the other way around. However, all that doesn’t stop the developers from designing and launching completely new or even slightly modified and refreshed old models. One these companies is XIGMATEK Co., Ltd. And our today’s review will be devoted to three of their cooling solutions. They are Cobra, Nepartak and Dark Knight coolers.
The first new cooling solution we are going to discuss today ships in a compact square box with small cut-out windows on two adjacent sides that reveal part of the cooler:
Cobra cooler sits in clear plastic casing inside the cardboard box that was partially cracked on the way to us. The cooler is bundled with an LGA775 retention kit, a swing-clip for AMD processors, five silicon spindles for the fan, a pack of Stars thermal paste and installation manual:
XIGMATEK Cobra is very compact, it measures only 132 x 92 x 102 mm and weighs 452g. in my opinion, the design of the cooler is fairly simple and consists of an aluminum heatsink that touches the base and is pierced with four heatpipes. Each heatpipe is 8mm in diameter and forms part of the cooelr base plate (HDT technology):
The shape of XIGMATEK Cobra does in fact remind of a poisonous viper ready to strike. This is where the name of this cooler is probably coming from.
The cooler heatsink is topped with a 92 x 92 x 25 mm fan that is very easy to take down:
The heatsink array consists of 46 flexible aluminum plates of two types. 30 smaller plates sit just on the heatpipes, while the remaining 16 hold on to heatpipes and an aluminum block above the heatpipes in the cooler base.
The heatsink plates are spaced out at a 2mm distance from one another and are 0.45mm thick. Despite complex heatsink shape and profile, we managed to calculate its effective cooling surface area - 3,183sq.cm, which is one of the largest among mainstream air-coolers.
The heatpipes are positioned non-linearly inside the heatsink: two side heatpipes are a little above the middle pair:
The gap between the 8-mm heatpipes in the cooler base is 1.5mm and filled with aluminum:
The base surface is very even and finished in a manner typical for HDT-bases: moderately smooth without any polishing.
We use four shock absorbent silicon spindles (the fifth one must be a replacement one) to install a 92-mm fan onto the Cobra heatsink:
The fan rotation speed is PWM controlled from 1200 to 2800RPM. The claimed airflow is 39-54.6CFM while the noise is promised to stay within 20-28dBA. The fan uses a rifle bearing with 50,000 hours or 5.7 years of non-stop operation time before failure.
The fan consumes maximum 3.6W of power at 0.3A electrical current.
XIGMATEK Cobra is designed for contemporary Intel and AMD processors for Socket LGA 775 and Socket 754/939/940/AM2(+)/AM3, respectively. All retention components are fairly simple and pretty reliable (for this particular cooler):
Too bad the new cooler is not yet compatible with the LGA1366 platform. However, XIGMATEK has already solved this problem, which we are going to dwell on later in our today’s article.
There is no mention about the preferable XIGMATEK Cobra cooler positioning during installation, neither in the enclosed manual, nor on XIGMATEK’s official web-site. That is why I checked out the dependence of cooling efficiency on the solution orientation on my own. It turned out that when the cooler is installed with the ends of its heatpipes facing up:
…it cools the CPU 3°C better under maximum load than when the heatpipes are directed horizontally. We have already seen top-coolers demonstrate the same dependence in tower-cases (the most recent example is Scythe Kabuto).
In conclusion I would like to add that the recommended price of XIGMATEK Cobra cooler is $27.
The box of the second new cooler we are discussing today – XIGMATEK Nepartak – is a little bigger in size, but is also made of cardboard and has a small cut-out window on the side:
The accessories bundle is exactly the same as the one that comes with Cobra. The only difference is the thermal interface: there is a pack of SilMORE paste instead of Stars:
The cooler name – Nepartak – is the name of a tropical cyclone that hit the Philippines in 2003. I haven’t checked what was so special about that particular cyclone, but the cooler itself looks quite common:
It is a tower-cooler measuring 99.5 x 62.7 x 134 mm and weighing only 634.4g, which is not too much according to today’s standards. 42 aluminum plates, each 0.385mm thick sit on three copper heatpipes, each 8mm in diameter:
The gap between the heatsink plates is 2mm and the calculated effective cooling surface of the heatsink is 4,313sq.cm. Speaking of the heatsink peculiarities, I have to point out that its plates are slightly inclined to the bottom along the airflow route and there are short slits along their edges:
These slits are most likely made to create turbulent airflow on leaving the heatsink. But why would they need it, is fairly hard to tell. Looks like XIGMATEK engineers considered these slits to be really important if they decided to add one more operation to the manufacturing process.
The heatpipes in the base of the cooler are spaced out at 2.7mm from one another, which is quite a lot compared to Cobra cooler we have just discussed above. It may have some negative effect on the heat transfer. At the same time, the base is very even and covers the entire CPU heat-spreader:
XIGMATEK Nepartak is topped with exact same fan as Cobra: it has the same dimensions, number of blades, marking and even color. However, they claim that this fan has slightly different specs (see table below). The fan is installed onto the heatsink with shock-absorbent silicon spindles:
The XIGMATEK Nepartak installation procedure is very simple and intuitive. It installs almost the same way as Cobra cooler:
Unfortunately, the new cooler cannot be installed onto LGA1366 mainboards with the bundled retention kits.
We tested XIGMATEK Nepartak efficiency inside the system case and it proved barely dependent on the way you install it. 1-1.5°C is the most you could win by installing the cooler like this:
The interesting thing is that this cooler is priced even lower than Cobra. Its MSRP is set at $25.
Finally, the third and the last cooler we are going to discuss today has a very remarkable name: XIGMATEK Dark Knight, just like the last Batman movie with Christian Bale. The box for this cooler is designed in dark colors with a knight sword on the front:
There is a polyurethane foam casing inside the cardboard box that holds the cooler securely and protects against possible transportation damage. The cooler is bundled with an LGA775 backplate, two retention brackets with screws for the same platform, five silicon spindles for the fan, a swing-clip for AMD processors, Stars thermal interface and installation manual:
I think XIGMATEK Dark Knight is one of the most beautiful processor coolers out there. A fully-nickel-plated tower with a dark semi-transparent fan creates inimitable mood and stresses the serious intentions of the “Dark Knight”:
By the way, the manufacturer specifically points out on their web-site that “Black Nickel causes a very gentle but also noble image, which also increases cooling performance.” However, from my conversations with other cooling solution manufacturers I learned that nickel-plated heatsink samples would usually be about 4°C less efficient on average, than the same exact heatsinks without the nickel layer.
The cooler design is fairly simple. There is a heatsink made of 54 aluminum plates, each 0.45mm thick that are spaced out at 2mm from one another. These plates sit on three copper heatpipes, each 8mm in diameter:
The heatsink measures 120 x 50 x 159 mm and its calculated effective surface area is 5,539sq.cm.
Just like by other two coolers we have just discussed, the heatpipes of XIGMATEK Dark Knight form part of the cooler base. It comes covered with a protective plastic film:
The distance between the heatpipes in the base is 2.7mm. The base surface is very even and is nicely finished:
Just like by the previous two XIGMATEK coolers, the fan of XIGMATEK Dark Knight is installed onto the heatsink with four silicon spindles:
The fan is a 120 x 120 x 25 mm model. It has 7 blades and rotates at 1000-2200RPM, which is PWM controlled.
The fan may create up to 89.45CFM airflow at its maximum rotation speed with 4.01 mmH2O static pressure and 30.1 dBA noise. The manufacturer doesn’t mention these parameters for the minimal fan rotation speed. The rifle bearing used for this fan should guarantee 50,000 hours or over 5.7 years of non-stop fault-free operation.
The new cooler supports all contemporary AMD platforms and Intel LGA775 platforms. It installs the same way as Cobra and Nepartak coolers with that only difference that on LGA775 it doesn’t use the plastic clips anymore, but is screwed on to the backplate through the mainboard PCB:
It is a definite advantage, because screws hold the cooler better than plastic clips and hence ensure more secure contact with the CPU heat-spreader. The drawback here is also evident: you will need to remove the mainboard from the system case to install the cooler, so the process will require more time and effort on your part. Unfortunately, there is no retention kit for LGA1366 platforms bundled with the XIGMATEK Dark Knight yet.
During our test session e installed XIGMATEK Dark Knight two ways: with the airflow directed towards the back of the system case:
… and towards the top of the system case:
In the latter case when the heatpipes run across the processor socket lock, the peak CPU temperature was stably 3°C lower than when the cooler was installed as shown on the first two photos. We have already discussed this peculiarity of Intel Core i7 processors cooling in our earlier articles.
The fan has white LED lights that look very attractive in the dark:
Despite its size, design and unique looks, the recommended retail price for XIGMATEK Dark Knight is only $37. Now that we have taken a close look at this cooling solution we can conclude that it is actually XIGMATEK HDT-S1283 made back in 2007. Although now it has a nickel-plated heatsink, new fan, different LGA775 retention kit and slightly lower price (it used to be $44). But in fact, it is the same good old HDT-S1283. So, maybe the economic crisis did hit the cooling solutions market after all?
LGA1366 platform for the new Intel Core i7 processors become more and more popular. XIGMATEK understood the situation very well and released two retention kits for the new platform. However, XIGMATEK decided to do more than just an LGA1366 retention kit; they also made it compatible with LGA775. So, if for some reason you are not happy with the plastic clips bundled with your cooler, you can use an alternative retention.
Both Crossbow kits are shipped in small cardboard boxes. You can find the list of supported coolers as well as step-by-step installation instructions for the retention kits right on the box:
As we have said, there are two kits: Crossbow ACK-I7361 for XIGMATEK HDT-S963, HDT-S1283, Red Scorpion-S1283, Nepartak S983; and Crossbow ACK-I7363 for XIGMATEK HDT-D1264, HDT-D1284, Achilles S1284C, HDT-SD964, Cobra D984. The kits include a backplate with sticky padding, spring-screws, two retention brackets and screws with a wrench:
The only difference between these two kits is in the type of retention brackets that are attached to the cooler base and in the bundled screws. Each kit runs for $6.
All tests were performed inside a closed system case. Our testbed was identical for all coolers throughout the test session and featured the following configuration:
All tests were performed under Windows Vista Ultimate Edition x86 SP1. We used the following software during our test session:
So, the complete screenshot during the test session looks as follows:
The stabilization period for the CPU temperature between the two test cycles was about 10 minutes. We took the maximum temperature of the hottest processor core of the four for the results charts. The ambient temperature was checked next to the system case or open testbed with an electronic thermometer with 0.1°C precision that allows monitoring the temperature changes over the past 6 hours. During our test session room temperature stayed at 23.5-24°C.
The noise level of each cooler was measured after 1:00AM in a closed room about 20sq.m big using CENTER-321 electronic noise meter. The measurements were taken at 1m and 3m distance from the closed system case. During the acoustics tests all five 120-mm case fans were slowed down to ~520 RPM. In this mode the background noise from the system case measured at 1m distance didn’t exceed ~33.3 dBA. When the system was completely powered off, our noise meter detected 30.8 dBA (the lowest on the charts is 30 dBA). The subjectively comfortable noise level is around 34.5~35 dBA.
Besides three new coolers from XIGMATEK discussed before, we are going to compare their cooling efficiency against that of the best XIGMATEK cooler – Thor’s Hammer. This cooler ships without a fan that is why we tested it with a fan from Dark Knight i9n two speed modes:
The second cooler we picked for our today’s comparison is going to be Thermalright IFX-14, which is the most efficient CPU air cooler today. Of course, we can’t compare our today’s testing participants and the IFX-14 in weight, size and price, but we are not talking about any direct comparison here. The only reason why we included the IFX-14 is to get a sort of reference point and be able to determine how far behind the today’s main heroes are.
As you can see from the photo, Thermalright IFX-14 was tested with one fan installed between the heatsink arrays. It was the same exact fan as the one on XIGMATEK Thor’s Hammer or Dark Knight. I would like to remind you that all XIGMATEK coolers were installed with screwed retention kits during the test session.
Using the “weakest” cooling system of the today’s testing participants we managed to overclock our 45 nm quad-core processor to 3.84 GHz (+43.8%). The nominal processor Vcore was increased to 1.31875 V in the mainboard BIOS (+9.9%):
During CPU overclocking we activated in the mainboard BIOS the “Load-Line Calibration” function that lowers the voltage drop on the part of the voltage regulator circuitry before the CPU. The system memory voltage was locked at 1.525V and its frequency was at 1500MHz (8-8-8-18 timings). All other parameters available in the mainboard BIOS and connected with CPU or memory overclocking remained unchanged (set to Auto).
The obtained results are given on the diagram below in order of increasing cooling efficiency (lowering of the peak CPU temperature):
XIGMATEK Cobra turned out the least efficient cooler in our today’s test session. Although, frankly speaking I expected this cooler to be at least as good as Dark Knight if not the best of the three. Looks like small effective surface area of the cooler heatsink prevails over the four heatpipes sitting closely to one another in the cooler base. Even a slightly cheaper Nepartak with one heatpipe less and almost twice the gap between the heatpipes in the base is about 4°C more efficient than Cobra in quiet mode and all 9°C better at maximum fan rotation speed. BY the way, Nepartak turned out 1°C better than a more expensive Dark Knight, although it noise level was also higher this case.
Dark Knight proved to be the best cooler of the three discussed today. It is only 2°C behind XIGMATEK’s flagship Thor’s Hammer solution at maximum fan rotation speed. The latter, even at maximum fan sped, yields to Thermalright IFX-14 3°C and 5°C in both modes respectively. By adding the results of this super-cooler into our today’s tests gives us a better idea of its advantage over the competitors even during moderate CPU overclocking for Thermalright IFX-14.
Since Cobra and Nepartak coolers are equipped with identical fans, they demonstrated identical acoustic characteristics (at the tested speeds). So, their results have been combined on the diagrams:
Everything is quite expected here: all three coolers are within the subjective comfort zone in the quiet fan mode, and at maximum speed – they are just a little past the comfort zone limits.
The new coolers from XIGMATEK we discussed today proved absolutely worth the price they ask for them. Two least expensive solutions, Cobra and Nepratak, will suit perfectly for moderately overclocked quad-core processors. Although the second cooler is more efficient than the first one, I personally pinned bigger hopes over the Cobra. The third testing participant – Dark Knight – turned out very efficient. It only fell a tiny bit behind Thor’s Hammer. Besides, Dark Knight creates lower sound pressure and looks remarkably attractive. Yes, it is about $10 more expensive than Cobra or Nepartak, but in my opinion, this extra money is totally worth paying. Anyway, as always, the choice is yours. As for us, we would like to wish XIGMATEK to include LGA1366 retention kit into the standard cooler bundle, because it will make things so much more convenient for users.