Thermally controlled fans on CPU heatsinks attempt to provide silence whenever possible, and maximum cooling ability when needed. It’s simple in concept, but very difficult to make work in practice. Arctic Cooling have been doing it for a while. Russ examines their latest iteration for socket-A, the Copper Silent 2 TC. It is a thumbs up for the SPCR audience.
Oct 8, 2003 by Russ Kinder
Product: Arctic Cooling Copper Silent 2 TC (rev 2)
Manufacturer: Artic Cooling
Supplier: Frontier Computer
MSRP: US$20
Thermally controlled fans on CPU heatsinks attempt to balance the best of both worlds: Silence whenever possible, and maximum cooling ability when needed. Its simple in concept, but very difficult to make work in practice. In order to work well, a whole range of features must be combined in a single unit:
- It must be based on an efficient heatsink.
- It must have a fan that has an excellent noise/CFM ratio.
- The fan must operate well across a range of speeds, without buzzing or clicking as the voltage changes.
- It must have a thermal control system responsive enough to adjust quickly to changes heat output, while not making the fan speed changes so obvious and abrupt to be annoying or intrusive.
Finding a heatsink that does any one of these things well is a rarity, but Arctic Cooling has presented their Copper Silent 2, which they hope will do all of them well, and for only US$20 at that.
SPECIFICATIONS
Recommended for All AMD Duron
& AMD Athlon XP up to 3200+
Heat Sink: 84 x 76 x 41 mm
Copper Plate: 44 x 44 x 5 mm
Overall Dimensions: 88 x 82 x 79 mm
Rated Fan Speed: 2200 RPM
Power Consumption: 12 V, 0.13 Amp.
Air Flow: 29 CFM
Weight: 395 g (including fan)
Noise Level: 18 dB
Thermal Resistance: 0.30 °C / Watt
It should be noted that no details are given for the noise level and thermal resistance measurements, although it could be assumed that the noise measurement was made at 1 meter with the fan at the minimum RPM and the resistance with the fan at max.
THE DESIGN
The heatsink is a fairly large aluminum extrusion 84m long by 76mm wide. The 26 fins are 41mm tall and are widely spaced and tapering. Soldered to the bottom of the aluminum is a 44 x 44 x 5 mm copper plate. The plate is located off-center relative to the rest of the heatsink, so that it is centered over the CPU die when installed. By placing the copper plate at just the heat source Artic Cooling hopes to gain the most benefit possible from the copper, while minimizing the added weight and cost of heatsinks that make more extensive use of copper.
Artic Cooling uses “a super-thin tin film” as the bonding substance between the copper plate and the aluminum, which “has the advantage of approx. 25-times higher heat conductivity of tin compared with the thermal compound” often used for such interfaces. Some of this bonding tin can be seen on the edge of the copper plate in the photo above. (Are they saying they do more than just screw the copper plate to the aluminum? Could “a super-thin tin film” possibly be a type of… solder?! Indeed, that’s precisely what it is.)
The attachment mechanism on the CS2 is nothing revolutionary, but is well made and easy to use. The clip is symmetrical, with a screwdriver notch and pivot point at each end. Having each end be the same makes it easier to install the unit inside a case, and the pivots allow you to hold one end over the lugs while pressing the other side down to secure it. It is easier to use than the original AC Super Silent Pro TC’s “tool-less” clip.
While the heatsink is rather conventional, that 80mm fan mounted atop it is nowhere close to a normal fan. For starters the motor is mounted well above the fan blades on little stilts. This arrangement reduces the turbulence noise from the motor supports, while allowing the fan to be as close to the HS as possible. We’ve seen it before in the Arctic Cooling Super Silent 4 Pro TC. They claim “the patented ‘reversed-hanging’ fan is able to practically eliminate the typical buzzing sound of 80mm fans.”
FIT & FINISH
The copper plate is machined smooth, but not highly polished. There are fine machine marks that can be felt with the fingernail. The mating surface is musical while being cleaned — that is, it makes noise when an acetone-soaked swap is wiped across the surface. Thats a sure sign that there are surface imperfections remaining. Lapping would probably provide a few degrees improved performance.
TESTING
Due to the thermal-controlled nature of this HSF the standard SPCR methodology doesnt apply. Instead it’s tested as an integrated unit at the standard 12V fan voltage with measurements taken of temperature, RPM, and noise level.
The Test Bed:
- Abit NF7 motherboard, with latest BIOS revisions. Modified with passively cooled NB.
- XP2100 Thoroughbred B, at stock speed and voltage (1.65v, 62.1 Watts max)
- 1GB of PC2100 RAM.
- ATI 9500 graphics card, passively cooled with Zalman Hp-80A heatpipe cooler.
- Seagate Barracuda IV hard drive.
- Enermax 365 PSU, modded with an L1A @7 volts.
- 80mm Panaflo L1A reference fan.
- Temperatures are read from the internal thermal diode of the CPU with https://silentpcreview.comhttps://silentpcreview.com<!–/–a> continuously until the temperature stabilized, generally at least 30 minutesTest Results
The Thermalright SLK800 data is included as a check against a known reference. It was measured on the same test bed under the same conditions. The room ambient temperature was a constant 22°C .
Heatsink Temp °C – IdleTemp °C – LoadDelta T in °C°C/WFan voltage 12V7V12V7V12 V7V12V7VFan RPM 1400–1750–––––AC CS2 42–57–35–0.56–SLK-800 324140.557.518.535.50.30.57Its pretty clear from the results that the CS2 follows a similar philosophy as the first Arctic Cooling heatsink reviewed by SPCR. The idle temp is fairly warm at 42°, but the noise from the fan at this speed is very low, probably silent inside a normal case. At load the CS2 runs about even with the heavyweight SLK-800 with a 7V Panaflo 80L1A, but produces a bit more noise. The quality of its noise is a little rougher, too, with a touch of some buzzing beneath the whooshing of the wind turbulence.
This fan is not spinning at full speed at the maximum temperature reached during testing. Its thermal / RPM calibration appears to be similar to the one employed in the Arctic Cooling Super Silent 4 Pro TC, which rose up to 2500 RPM only when artificially heated up with a hot hair dryer. The following graph from AC demonstrates the relationship between fan speed and temperature.
Our measurement of 1750 RPM at 57°C is very close to what is shown on the graph. Interestingly, the fan IS capable of spinning as fast as 2800 RPM, but only when the temperature is at 80°C.
In short, this HSF is optimized for low noise and decent cooling rather than good cooling and mediocre noise. That’s fine for most of the SPCR audience.
Conclusion
The CS2 is a nice refinement of ACs earlier socket-A coolers. While its cooling performance at low noise is modest, it strikes a good balance between performance, low noise and cost. Don’t use it with your latest, fastest XP if you want it to stay running quietly — not without some very careful case airflow optimization — but for lots of middle and budget systems, the Arctic Cooling CS2 is perfectly good and very nicely quiet for a very modest price. Basically, we like it a lot.
Our thanks to Arctic Cooling and Frontier Computer for the Arctic Cooling CS2 samples.
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