by Sergey Lepilov
08/30/2007 | 12:09 PM
Everything in the design of air coolers with heat pipe technology seems to have been long invented and tested. We have examined a great number of tower-like coolers that can be regarded as classics today, tested coolers with only one large-diameter heat pipe, checked out orb-like heatsinks with heat pipes, and even launched a couple of heat-pipe “rockets” (into the trash bin so far). So, coolers with heat pipes have been represented in our laboratories’ tests extensively.
<%BANNER[article]%>Meanwhile, cooling system makers are still developing and introducing new solutions notwithstanding the temporary halt in the growth of heat dissipation of modern CPUs. Different brands take different approaches. Particularly, Zalman positions its new CNPS8700 LED as a cooler for compact and low-profile system cases. According to the press release, the new cooler still features high performance (and cools the near-socket space on the mainboard) while working with little noise.
Thermaltake, on the contrary, did not bother about the dimensions of their new cooler called Thermaltake V1, but tried to make it appealing to overclocking aesthetes who enjoy a cooler’s appearance no less than they do its performance. I won’t evaluate the aesthetic properties of the V1 in this review as you can easily do it for yourself looking at the photographs, but I will check out the Zalman CNPS8700 LED and the Thermaltake V1 from an overclocker’s point of view.
The new product from the Seoul, Korea based Zalman is shipped in the traditional packaging of the brand. The external wrapper is a cardboard box with cut-outs in its face and reverse sides:
You can find product specs, a list of supported CPUs and platforms, key product features and other information by examining this package. Inside this box there is a plastic jacket that envelops the cooler tightly. Accessory items lie on top:
The Zalman CNPS8700 LED looks like the good old Zalman CNPS7000 and 7700 that used to be considered fantastically efficient coolers. The specific bowl-like shape of the heatsink leaves no room for a mistake.
But as soon as you take a look at it from a side or from below, you realize it is quite different from the copper chunk weighing near 1kg.
The cooler is based on two copper heat pipes, 6mm in diameter. They go out of a copper base covered with an aluminum plate from above and carry a large number of copper ribs, only 0.2mm thick.
The pipes go around in two tiers, distributing heat evenly in the ribbing, and end in the base. The cooler is rather low by today’s standards. Its height is a mere 67mm and it weighs only 475g. Each rib sports a stamped name of the manufacturer.
To make the whole design more rigid, the heat pipes are soldered to one another in the place of contact:
The pipes are soldered to each other in the base as well:
If you remove the fan and the fastening plate, you can see the soldering between the pipes is not uniform:
Yet this is just a cavil on my side. More important is that not only the meeting point of the pipes but also the places of contact between the copper base and the pipes of the “bowl” be soldered together well.
The aluminum plate screwed to the base and covering the pipes performs the function of a foundation for the mounting clip and has no contact with the pipes.
The fan impeller is fastened to it too by means of two aluminum feet:
The Zalman CNPS8700 LED employs a 110x25mm fan, i.e. a standard impeller of a 120mm fan. The fan is marked as ZF1125BTH and runs on two ball bearings. Its speed is regulated by means of the included Fan Mate 2 controller within 1150-2350rpm. When connected directly to the mainboard (without the Fan Mate 2), the fan speed is 2550rpm at 35.5dBA of noise.
The cooler’s base is flat and perfectly polished:
It’s been a while since I last saw such a high-quality cooler surface. Bravo, Zalman!
The Zalman CNPS8700 LED can be installed on every modern platform. Zalman doesn’t count mainboards with Socket 478, let alone with Socket A (462), among such and the new cooler doesn’t support them. The cooler is fastened on Socket 754/939/940 and Socket AM2 mainboards by means of a clip with a detachable tip (included into the kit) that is hitched at the teeth of the standard retention frame around the socket. You don’t have to take the mainboard out of the system case for that, but you do if you are dealing with an LGA775 platform.
This is Zalman’s traditional LGA775 fastening mechanism employing a plastic frame you have to screw through the mainboard:
The frame is attached to a back-plate that prevents the mainboard from bending and increases the pressure of the cooler’s base on the CPU heat-spreader.
The components on the reverse side of the mainboard do not get in the way of this back-plate as I made sure on ASUS P5B Deluxe, P5K Deluxe and P5N32-E SLI mainboards.
And then the same clip is inserted between the pipes and hitched on the plastic frame.
As you see, the cooler is compact and its bottom “skirt” doesn’t go outside the area of the plastic frame. Zalman specifies the installation requirements for each platform with the following pictures:
According to them, there should be no elements on your mainboard taller than 39mm within 61.5mm from the center of the CPU.
Inside a system case the Zalman CNPS8700 LED looks like this:
It is very small in comparison with tower-like coolers. A soft blue light from the cooler’s fan will be visible at night.
The recommended price of this cooler is $40-50.
Thermaltake’s product is positioned as a stylish cooler for enthusiasts. The box is big but the cooler is largely open to the potential buyer’s eyes.
There’s a lot of information on the box. The cooler has a tight-fitting plastic jacket sealed with sticky tape:
So, nothing is going to fall out of the box or get broken during transportation. You’ll find a small cardboard box with accessories at the bottom of the package.
It contains two LGA775 fasteners with screws, a clip for Socket 754/939/940/AM2, an installation guide, and a pack of thermal grease.
Let’s take a look at the Thermaltake V1:
That’s original indeed. I haven’t seen any cooler designed like that before.
The cooler’s heatsink consists of two fan-like parts (this must be the reason why the cooler is called V1) each of which hangs on a couple of 6mm heat pipes:
So, this cooler employs four pipes rather than two as in the Zalman CNPS8700 LED. There are a total of 102 ribs here (2 x 51), each 0.2mm thick. The ribs have contact with the pipes by means of thermal glue rather than solder as would be ideal. As a result, you can even move some ribs a little along the pipes. They don’t hang loosely by themselves, though.
Nestled between the two heatsink halves is an impeller from a 120mm fan. It is 110mm in diameter.
The airflow from the fan goes to both heatsink halves at once: an incoming flow for one and an outgoing flow for the other. The heatsink is braced with a couple of plates on each side for more rigidity. The ends of the heat pipes go into these plates.
The fan impeller is fastened on a metal pole in one position.
I mean you can’t turn the fan around to change the direction of its airflow, yet I don’t think anyone would want to do so. By the way, this TT-1225A (Everflow) fan is equipped with three blue LEDs.
A speed controller is attached to the fan. It looks like a small tail:
The cord is short and it is rather inconvenient to control the speed inside the system case. Anyway, this controller allows varying the fan speed from 1300 to 2000rpm at 16 to 25dBA of noise (Thermaltake traditionally understates the level of noise). This fan creates a max airflow of 86.5CFM.
This is a photo of the cooler from below:
The pipes in the base are soldered together like in the Zalman CNPS8700 LED:
The plate that the fan and the mounting plates are fastened to resembles the one of the Zalman cooler, too. It has no contact with the pipes.
The Thermaltake V1’s bottom is not a mirror, yet its finish quality is high:
The bottom is perfectly flat as I checked out by looking at the trace of thermal grease it left on a piece of glass.
Mounting this cooler on the supported platforms is very easy. The Thermaltake V1 is fastened on K8 CPUs by means of a clip that is inserted between the heat pipes and is then hitched at the teeth of the retention frame. The orientation of the cooler inside the system case is limited to two positions and depends on the orientation of the retention frame around the CPU socket.
If you’ve got an LGA775 platform, you should first secure the fasteners with plastic locks on the cooler’s bottom:
Then you carefully insert these locks into the mainboard’s holes. The pressure is strong enough to ensure a proper heat transfer. The cooler doesn’t turn around on the heat-spreader. The Thermaltake V1 can be oriented in every direction on LGA775 processors. As you’ve understood from the description of the installation procedure, you don’t have to take your mainboard out of the case whatever platform you use.
The Thermaltake V1 is compact on the mainboard and is unlikely to have conflicts with the near-socket components:
Here is how the new cooler looks like inside a system case:
Note that the cooler is oriented differently in these two photos. In the first photo the heat pipes are parallel to the rear panel of the system case. In the second photo they are perpendicular to it. The installation guide doesn’t tell which orientation is better. As a matter of fact, the spatial orientation doesn’t affect the performance of a heat pipe, so Thermaltake doesn’t put a focus on this issue. And I didn’t find any difference in the cooler’s performance arising from its orientation.
The Thermaltake V1 comes at a recommended price of $40-50, comparable to that of the Zalman CNPS8700 LED.
The following table lists the specs and recommended prices of the tested coolers:
The coolers were tested on an open testbed and in a system case with the following configuration:
I’ll explain in the Results section why I had to use a dual-core CPU instead of the traditional quad-core model.
All tests are performed in Windows XP Professional Edition Service Pack 2. SpeedFan 4.32 is used to monitor the temperature of the CPU, reading it from the CPU sensor. The CPU is heated up by means of OverClock Checking Tool version 1.1.0 in a 24-minute test during which the system remains idle in the first and last 4 minutes.
The mainboard’s automatic fan speed management is disabled for the time of the tests. The thermal throttling of the Intel Core 2 Duo processor is controlled with RightMark CPU Clock Utility version 2.25. Our CPU begins to skip clock cycles on reaching a temperature of 82°C and higher.
I perform at least two cycles of tests and wait for 20-25 minutes for the temperature to stabilize during each test cycle. The maximum temperature of the hottest CPU core in the two test cycles is considered as the final result (if the difference is not bigger than 1°C – otherwise the test is performed once again). Despite the stabilization period, the result of the second cycle is usually 0.5-1°C higher.
The ambient temperature was monitored by means of an electric thermometer and remained at 28.5°C during the tests. The fan rotation speed is shown in the diagram as reported by monitoring tools.
I took two opponents to the tested coolers: Zalman CNPS9700 LED and Thermalright Ultra-120 Extreme. The Zalman CNPS8700 LED is about $20 cheaper than the CNPS9700 LED and is positioned differently on the market. So I guess it’s interesting to know how weaker the more compact and cheaper cooler is in comparison with Zalman’s top model. The Thermalright Ultra-120 Extreme is currently one of the best air coolers if not the very best one. So it makes a good point of reference. I tested the cooler from Thermalright with two very quiet 1100rpm Scythe Minebea fans installed for intake and exhaust.
Before discussing the results I want to tell you why I replaced the quad-four CPU with a dual-core one. It was due to the Thermaltake V1 that proved to be unable to cope even with our slightly overclocked Core 2 Quad (running at 3200MHz, 1.45V). In less than four minutes after the start of the test OCCT would report an error and abort (click here for details). I did not reduce the CPU frequency or voltage because the monitoring graph, which showed a straight line going at an angle of 45 degrees up, indicated that the problem was not about a too-high CPU frequency. Moreover, I had already learned that even cheaper coolers, let alone top-end ones, could cool the Intel Core 2 Quad at 3300MHz.
Of course I checked out the contact between the Thermaltake V1’s base and the CPU heat-spreader, but it was perfectly normal. Then I tested the cooler in two positions: with the heat pipes oriented vertically and horizontally. I got the same result: the error occurred with a 10-15 seconds difference in time. I even replaced the mainboard but this had no effect on the CPU temperature under OCCT. I suspected a defect of the particular sample of the cooler and requested another sample from Thermaltake but it showed exactly the same results. Quite frustrated I tried to check out the cooler on Intel’s dual-core model and was surprised to see it do no worse than the Zalman CNPS9700 LED! After all the tests, reinstallations and replacements I did with the Thermaltake V1 on my Intel Core 2 Quad, I think this cooler does not suit for cooling overclocked quad-core processors although this CPU is on the compatibility list.
That’s why I tested all the coolers on an Intel Core 2 Duo E6400. The highest frequency was determined by the weakest cooler in this review (in a closed system case). It was 3500MHz at a core voltage of 1.5V. The test results are listed below.
Breaking no records, the Zalman CNPS8700 LED and the Thermaltake V1 keep the CPU temperature at about the same level under peak load and are both slightly weaker than the more expensive Zalman CNPS9700 LED. Note that the Thermaltake V1 does not depend much on the fan speed when tested on an open testbed. Equipped with two fans, the Thermalright Ultra-120 eXtreme is beyond competition as was to be expected.
The following table shows the temperature of both CPU cores, the reading of the mainboard’s CPU sensor, and the reading of the mainboard’s sensor proper.
Note that the Zalman CNPS8700 LED copes best with cooling the near-socket space. This stands to reason since it is the single cooler in this test that directs its airflow towards the mainboard rather than along it.
Next I found out the highest CPU frequency I could achieve with each of the coolers. This test was performed on an open testbed. Here are the results:
These results make me confess that the Thermaltake V1 is more efficient than the Zalman CNPS8700 LED and even than the CNPS9700 LED. Note that the stable CPU clock rate was only 24MHz higher with the Thermaltake V1 when it worked at the max speed, but its noise grew considerably.
The next diagram shows the noise level of each cooler measured according to our traditional method (the subjectively comfortable level of 36dBA is marked with a dash line; the ambient noise from the system case, without the CPU cooler, was about 34dBA):
Alas, the Thermaltake V1 is not a very quiet cooler even at its min fan speed of 1370rpm (although it is only as loud as 36.9dBA in the most important mode) because the rumble of its fan is perfectly audible against the quiet system case. The subjective limit of 36dBA is only exceeded by 0.9dBA but it is enough for the cooler to get not exactly loud, yet irritating with its rumble. The Zalman CNPS8700 LED has much better noise characteristics.
So, I’ve checked out the new coolers’ performance and noise level. It’s time to sum up the results.
The conclusion is obvious here. The arrival of the Zalman CNPS8700 LED and the Thermaltake V1 makes two new good air coolers available for overclockers. The former is intended for compact system cases and for people who prefer quiet coolers, yet it doesn’t limit the overclockability of the CPU much. The latter has a somewhat higher performance (on dual-core CPUs) as well as an original exterior which is going to please owners of transparent system cases and modders. The only problem was the inability of the Thermaltake V1 to cope with an overclocked quad-core CPU (perhaps it even means total incompatibility of this cooler with such CPUs from Intel) whereas the Zalman CNPS8700 LED successfully cooled our Intel Core 2 Quad Q6600 running at 3.3GHz.
Anyway, I’m sure if these coolers begin to sell at their recommended price, both of them will attract buyers and will live a long and happy life in overclockers’ PCs. Still, the choice is yours, especially as there is a very broad selection of air coolers in this price category.