Heatsink Construction & Design
Heatsink Construction & Design
Looking quickly at this cooler, you could make the argument that this cooler is nothing more than a revised and revamped ASUS Triton 75. Both are down draft style coolers (even if this one blows its air upwards instead of down), both use heatpipes with a aluminum radiator fin assembly to remove heat from the CPU and both have a very stylistic and slick design to them. Of course this is overlooking many key differences and if ASUS actually considers the Triton 77 be nothing more that a Triton 75 Rev 2.0 I would be very surprised. Unlike the 75 model this newer model is not a passive cooler and comes with its own 92mm fan. In fact the fan size that it accepts is even different that the 75 model. Also, the number of heatpipes has been increased from 4 to 5 and even the fins themselves are different. With the Triton 75 the fins went straight across from left to right and are similar in design to many tower style coolers (in that the top edge has indents to help reduce static air pressure). Contrast that very standard and relatively boring design against the 77 curved fin assembly that not only curve up and down (to give it that unique Seashell shape), but also left and right in a zigzag formation.

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Speaking of the aluminum fin assembly, these fins have been nickel platted to give them an extra shiny appearance that greatly enhances the looks of this cooler. In total there are 37 of these .4mm fins which are stacked very close together (approximately 2mm apart). This doesn’t give the Triton much surface area to work with and is in fact a lot less that the Triton 75 (the 75 has 55 fins). For modern CPUs this decrease in surface area usually corresponds to an increase in temperature. It would not surprise us in the least if ASUS engineers were forced to rework the design of the fins to keep the static air pressure low and this would also help explain the practicality of the unique pattern of the fins. Hopefully, the design of the fins allows air to move quicker over the fins and thus make up for it lack of size with increased efficiency. Only time and testing will give us the answer.

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Before we move on I would also like to mention that not only are the fins soldered to the heatpipes; the fins are also stamped/pressed together on each side so as to keep them from moving. This leaves two large ugly looking "scars" running down the left and right side of the fins assembly, and to a certain extent this ruins the striking good looks of this unit. However this reduction in good looks is more than made up in the stiffness of the Triton. While the heatpipes exhibit a lot of flexing, the fin assembly does not.
There is a potential negative to this design and it is a big one: every degree celcius that it absorbs from the hot MOSFETs is a degree that it can’t easily absorb from the CPU. By cooling the hot motherboard MOSFET’s first you are in effect preheating the air that will be used for cooling the CPU. Or to put it bluntly this cooler is its own worse enemy in that the ambient temperature entering the heatsink will be (if ASUS’ claims are correct) 10 -15*C hotter. This means a room temperature that is 30*C will result in an ambient temp reaching the heatsink of 40 – 45*C! Due to the laws of physics air can only absorb a certain amount of heat in a certain amount of time; however, this amount of thermal energy is fairly high so increasing the temperature by a few degrees is not a deal breaker, rather it is an engineering obstacle that needs to be overcome. To help alleviate this potential negative impact, ASUS engineer’s availed themselves of a few of the tricks used in regular down draft coolers.

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The first of these tricks is actual the opposite of what one would like to see on a typical down draft cooler. In a normal down draft cooler you want to recycle the air and let it cool a heatsink attached to the baseplate. By recycling this air you are in effect helping to reduce the amount of thermal energy dispersed by the heatsink. However, if ASUS had placed a large heatsink with large fins on the base they would have actually compounded the preheating problem and made the Triton 77’s job that much harder. Rather than a larger heatsink, ASUS instead opted for a small, streamlined heatsink that is big enough to support the weight of the unit but has as small a surface area as possible. It is outside the box thinking like this that has made ASUS the 800lb gorilla of the motherboard industry.

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While reducing the amount of heat is all well and fine it doesn't address the real issue of dealing with the increase in ambient air temperature around the heatsink. The easiest way to increase the efficiency of any cooler is by simply adding more heatpipes. The more heatpipes the more potential heat can be dumped into the air. This helps explain why this cooler has 5 heatpipes vs. the 4 that the (normal down draft cooler / passive) Triton 75 uses. By increasing the heatpipes by 25% the Triton should in theory be able to handle a higher ambient temperature than the previous model.
The last but not least solution to the ambient temperature issue is to give the cooler a big enough fan, thus enabling enough air movement to make the issue a moot point. After all, when finesse fails brute force usually doesn’t and in the real world there really is no such thing as “overkill” when it comes to cooling today’s CPU’s. In the case of the Triton 77, the fan used is a low noise 92x92x25 mm fan. However, even though 92mm is not a small fan, this particular fan model is not exactly designed to push as much air as possible, as low noise is synonymous with low CFM. While it would have made the Triton 77 bigger and probably cost it some of its looks, if ASUS had left this model as big as the 75 a more practical 120mm fan would have more than likely fit. As it stands, one has to wonder if this fan can handle the static air pressure that all those closely mounted aluminum fins must surely create.
On the positive side, the heatpipe ends were not just pinched off as on some units but actually capped as well. These caps also help to increase the rigidity of the fin assembly. As a bonus these caps help perpetuate the Triton's good clean looks that would have completely ruined by a poorly done heatpipe seal job. Their shiny clean copper tops really contrast nicely against not only the bright nickel plating but even against the black plastic fan mount as well.
Overall this unit emphasizes finesse over brute force, yet form does not suffer from following function at al. This heatsink doesn't look like a German engineered car, rather it looks like a sleek and stylish Bentley. Yes it can get down a bogie but it also exudes an air of class and elegance that only Apple and (now) ASUS seem to be able to get right. This cooler looks like an ASUS product and while it is a bit more flexible than we prefer to see it does seem well designed and superbly constructed. In the end ASUS didn’t cut many corners in making this unit and it is truly a marvel of user friendly engineering.