by Sergey Lepilov
07/02/2007 | 03:58 PM
The Japan-headquartered Scythe has been steadily updating its air cooler line-up. They announced the second version of the "samurai sword" - Katana 2 - in April and then rolled out a cooler with a totally new design idea - Kama Cross - at the end of May. The former is an improved version of the original Katana while the latter is an absolutely new cooler with unique design.
Besides being new products, these coolers have one more common trait. Their heatsinks are designed in such a way as to drive the airflow from their fans towards the mainboard’s elements around the CPU socket. And while the Katana II represents a simple solution (the heatsink consists of tilted ribs), the Kama Cross embodies a more radical approach to the problem.
Let’s see how good these two models are.
The new cooler from Scythe is shipped in a small colorful box, all covered with text and pictures.
The blue label saying “Quad Core Ready” caught my eye right away. That’s exactly what I need. Besides the model name the box shows a list of supported CPU sockets, cooler specifications in a few languages, and a detailed description of the four key features of the new product:
Those features are:
The box is divided into two compartments one of which stores the following accessories:
Here is the new cooler:
The second version of the samurai sword has acquired a third heat pipe and has got larger overall. Its design is no different, though. The three heat pipes passing through the copper base distribute the heat flow among the heatsink ribs that are tilted downwards. A seven-blade 100mm fan is installed on one side of the heatsink:
The ribs are tilted so that the airflow went down to the mainboard surface to cool the components around the CPU socket.
Each pipe is topped with a decorative cap and every heatsink plate has a stamped logo of the manufacturing firm.
The cooler’s base is protected with a piece of polyethylene film with a warning that you must remove it prior to installing the cooler.
The cooler’s sole is flat and superbly finished as is typical of Scythe’s products.
The copper plate of the base is 3.5-4 millimeters thick. The contact between the heat pipes and the copper plate is established by means of soldering.
By default the Scythe Katana II is equipped with a 100mm fan from Kaze Jyu (the SY1025SL12M model) running on a slide bearing with a constant speed of 1500rpm, creating an airflow of 42.69CFM and generating 22dBA of noise.
The fan is very quiet, subjectively. Its exact level of noise will be measured in the appropriate section of the review.
The fan is fastened with one clamping screw in the bottom part of the heatsink:
This fastening mechanism allows replacing the stock 100mm fan with a higher-performance 100mm or a 120mm one. The only requirement is that the fan is no more than 25 millimeters thick, too.
It is easy to mount the Scythe Katana II on any mainboard. You secure an appropriate fastening frame on the cooler’s sole with four screws and then install the cooler on your mainboard. You don’t have to take the mainboard out of the system case and the cooler can be oriented in any direction you choose thanks to its symmetrical fastener. The pressure force is high and the mainboard bends a little under it.
Installed on a mainboard inside a system case the Scythe Katana II looks like follows:
As you can see, the cooler is compact. The distance from its bottommost rib to the mainboard is just over 20 millimeters, so the mainboard’s components are unlikely to get in the cooler’s way.
The Katana II has a recommended price of $32.
The other newcomer from Scythe is shipped in a larger and no less informative package:
The text on the box describes the installation process, product specs, and four key features:
Those key features include the X-shaped heatsink design that drives the airflow from the fan towards the mainboard’s components around the CPU socket. The label indicating the support for quad-core CPUs is available, too.
There is another small box at the bottom of the package. It contains the following accessories:
The cooler is small and light at 140x120x132 and 530g, respectively. The heatsink resembles the letter X indeed:
Three heat pipes, about 6 millimeters in diameter, pass through the nickel-plated copper base. The ends of these pipes then intersect and each three-pipe group carries 37 aluminum ribs.
The pipes are bent in such a way that they do not interfere with each other. The aluminum ribs and the ends of the heat pipes are sealed with aluminum caps that support the fan.
The whole arrangement is topped with a 100mm fan:
The cooler design allows replacing the stock fan with a 120mm one using the appropriate holes:
The heatsink’s aluminum ribs are placed at a distance of 2 millimeters or less from each other and their ends are bent upwards to accept the airflow from the fan more effectively.
The cooler’s sole is covered with a piece of polyethylene film:
The sole is finished superbly:
I can’t find any fault with it.
The Scythe Kama Cross has the same fan as the Scythe Katana II:
Having the same fastening mechanism as the Katana II, the Kama Cross is installed likewise, too. Its heatsink hovers quite high above the mainboard, so it should get along nicely with the mainboard’s around-the-socket components.
The photos above show the Kama Cross installed in a position which is less advantageous in terms of cooling performance. The user manual recommends installing it in such a way that the pipes were horizontal rather than vertical as they are in the photos. However, I tried to use the cooler in both positions and found no difference between them as concerns CPU temperature.
The Kama Cross comes at a recommended price of $39.8
The following table lists the specs of the reviewed coolers from Scythe:
It has become a kind of tradition for us to test new coolers in comparison with the Cooler Master Hyper TX and the Thermaltake Big Typhoon. These coolers come from two difference price categories, costing $22 and $40, respectively. I consider these two coolers as best in their segments in terms of price/performance. They are also quiet at work and widely available. I think these are substantial reasons for this pair of coolers to serve as the reference point in our reviews.
It would have been interesting to compare the original Katana with the second version but I couldn’t find it. I was told the first Katana was out of production due to the launch of Katana II.
The coolers are tested on an open testbed as well as in a system case with the following configuration:
The peak CPU frequency was limited by the efficiency of the weakest cooler. The quad-core CPU was overclocked to 3213MHz (a frequency gain of 33.9%) with a voltage increase to 1.45V.
The mainboards’ 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.
All tests are performed in Windows XP Professional Edition Service Pack 2. SpeedFan 4.32 is used to monitor the temperature of the CPUs, reading it from the CPU sensor. The CPU is heated up by means of OverClock Checking Tool version 1.1.0 in a 25-minute test in which the system remains idle in the first and last 4 minutes.
The TAT program I had used earlier in my cooler reviews heats an Intel Core 2 Quad up by 2-4°C more than the OCCT does, but the OverClock Checking Tool is more practical and issues an error message if the CPU is unstable while the TAT goes on working under such conditions.
I perform at least two cycles of tests and wait for 25-30 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 24°C during the tests. The fan rotation speed is shown in the diagram as reported by monitoring tools.
The results are shown in the following diagram:
Unfortunately, the new coolers could not deliver very good performance. The Scythe Katana II coped with the overclocked quad-core CPU but maintained 9°C higher temperature under load than the cheaper Hyper TX from Cooler Master. I should acknowledge the much lower level of noise of the Katana II, though. The new coolers are beyond competition in this aspect.
The Scythe Kama Cross disappointed us despite its enlarged dimensions and higher price (in comparison with the Katana II). I reinstalled it and repositioned on the CPU but to no effect – its performance would not improve. Suspecting poor contact between the cooler and the CPU’s heat-spreader I checked it out and found it was normal:
Thus, in its standard version and in a closed system case the Scythe Kama Cross does not cope with an overclocked quad-core CPU and lets it begin to skip clock cycles. Replacing the stock fan with a 120mm one improves the cooler’s performance a little, yet it is still far from the performance of the Thermaltake Big Typhoon that costs the same amount of money. Thus, the more expensive of the new Scythe coolers proves to be less efficient. It may be better than the Katana II at cooling the mainboard’s near-socket area but I guess cooling the CPU must be the main priority. The optimization of the Kama Cross heatsink for cooling the near-socket area results in worse cooling for the CPU.
The amount of noise generated by the coolers was measured with a digital noise-level meter Center-321 (0.1dB accuracy) using A-curve weighing. The measurements were done at night in a totally quiet apartment – the level of ambient noise was as low as 31.6dBA.
The noise level was measured at a distance of 1 meter from a closed and fully functional system case (with the side-panel fan turned off) as well as at a distance of 3 centimeters when the CPU cooler was the only operating component. The comfortable level of 36-37dBA is marked with a dashed line in the diagram.
Each cooler is very quiet, but the two new models from Scythe are even quieter than their opponents. And we should give them due credit for that.
I have tested two new coolers from Scythe in this review and they have showed moderate thermal performance, but their pricing is non-competitive, at least at this time. Right now there are more efficient coolers available that are comparable to or cheaper than the Katana II and Kama Cross.
The indisputable advantages of these coolers are their very low noise level, universal and simple retention mechanism for each platform, free positioning of the heatsink on a mainboard with any type of CPU socket, and low weight. As we saw in case of Kama Cross, you can improve the cooler performance by replacing the stock 100mm fan with a 120mm one, however it still does not make the cooler competitive against other coolers with a comparable price.