Introduction and Technical Specification
German manufacturer Alpenfohn specialise in cooling solutions. Whether it be VGA, netbook or just old plain and simple fans. The K2 comes from their mountain range (Sorry couldn't resist) of CPU coolers and is currently the biggest cooler Alpenfohn produce. I do get the feeling that by naming it after the second highest peak in the world Alpenfohn have left themselves a bit of room for an even larger cooler should they decide that the K2 simply isn't big enough
Standing 160mm tall, with twin towers and no less than 8x6mm heat pipes the K2 falls into the category of super tower, directly challenging the likes of the D14 and the Silver arrow.
Specifications 120mm Wing Boost fan:
Specifications 140mm Wing Boost fan:
Twin tower with 8*6mm Heatpipes
Wing Boost 120/140mm Dual-Combination
Up Close: Packaging and contents
The K2 comes in an un windowed cardboard box resplendent with it's own pop out carry handle. As usual the box has pictures of the cooler inside as well as giving details of specification and features. Opening up the packaging is reminiscent of opening up a Russian doll, as there are boxes within boxes requiring a bit of a think as to how to get the contents out.
Contents wise, aside from the cooler itself we get 2 fans, 1x140mm and 1x120mm. The fans are nicely made and are finished in that soft touch plastic that I can't help but find very tactile. Also included are all the mounting screws and necessary brackets as well as a multi-socket back-plate. Spring-clips to secure the fans, a molex adapter, instructions and a small syringe of TIM complete the package.
Up Close: The Cooler
The K2 is of the twin tower type, with 49 Aluminium fins in each stack. Each stack is 50mm deep by 140mm wide at their widest point. The 8x6mm heat pipes are distributed evenly in a linear pattern along the length of each stack.
The leading and trailing edges of the fins are left open for air to pass though, but as is becoming quite a common feature these days, the sides of the fin stacks are closed off giving a smooth edge to each of the outer edges of each tower. The inner facing surfaces of the stacks have a saw tooth effect, whereas both of the outwards facing surfaces have a large trapezoid finish to them, presumably to aid airflow over the fins.
With the fans attached we get a better idea of the size of the K2. The fans can be mounted on either surface and in either direction, however it is intended that the 140mm fan sits in between the towers whist the 120mm fan sits on an outer surface. In mounting the fans it is of course necessary to pay attention to their orientations. If they're blowing towards each other they're not going to be doing a lot of good are they?
The fans themselves are quite nice little units. The 120mm is of the traditional square open corner construction whereas the 140 has a more circular outer cowling. both fans have mounting holes spaced for 120mm mounts and attach to the body by means of wire spring clips. The inner cowling of each fan is made of a White hard plastic and appears to be removable as with the BitFenix fans I reviewed a little while back. The black portion of each fan is finished in that rather sexy to the touch soft touch plastic rubber. Mmmmm Niiiice.
Up Close: Contact plate and heat pipes
The contact plate is CNC machined and has a mirror finished Nickel coating for that little bit of extra bling. The 8x6mm heat pipes are sandwiched between the upper and lower contact plates with all joins being soldered. There is a small gap of about 1.5mm between each pipe. The quality of the work is good, with no evidence of solder spitting or bluing from over heating.
The heat pipes angle progressively as their distance from the contact plate increases. Small bends in the pipes prior to passing into the fin stack allow to them to enter vertically into the stack. As a result the outer most pipes are angled through approx 45 degrees before entering the stack.
For such a large cooler the K2 was actually quite easy to fit. That said the job would have been much easier if the instructions didn't need a microscope to read them. I found the pictures that small that I actually resorted to taking several close up photos of the diagrams and then enlarged them on my PC so I could see what was going on. Combine that with a confusing and often hilarious German to English text and what we have is a set of instructions that actually appear to want to make the job harder than it is.
As I say the fitting itself, despite the intentions of the graphics department is actually a simple two stage affair. A multi socket back plate is attached to the rear of the case by means of threaded pins passing from back to front, with each of the legs having rubber isolation socks slid over them to prevent shorting on the rear of the motherboard. Brackets are then screwed to these pins on the front side of the motherboard using the relevant spacers depending on your socket type. After adding TIM to the CPU, the tower is then placed atop the chip where it is secured down by a cross brace. This brace has sprung screws to adjust tension and engages with the brackets on either side. The tower has to be installed without the fans in place but attaching them after is easy as the spring clips are nicely flexible. One in place each fan can be attached to separate headers or a fan controller or joined by a supplied adapter to enable them to be run from a single PWM header. Alpenfohn also include a fan-molex adapter if you want to go straight into the 12v supply from your PSU. There is also sufficient clearance underneath the unit for those who favour RAM with big heatsinks.
To provide continuity the test set up is as always
Gigabyte UD3R V2
Intel i7 950 @ 4GHz 1.25v & 1.35v
Mushkin Radioactive 2000MHz
Cooler Master Storm Trooper
For the first test we set our i7-950 overclocked to 200x20 @ 1.25v for a clock speed of 4.0GHz. We allow the system to idle for 30 minutes and then run Prime95 'maximum heat maximum stress' setting for a further 30 minutes
After 30 minutes we note the temperatures of all cores and the ambient temperature of the room. An average of all cores is taken, then the ambient temperature is removed from this figure and this gives us the delta temperature. Delta is the temperature difference above ambient which is a truer reflection of the heat-sink performance rather than mere maximum figures. Testing in an Igloo or the Sahara would give vastly different maximum temperatures, yet the Delta could be the same.
The second test follows all steps from above but with a 200x21 @ 1.35v for 4.2GHz overclock, the extra voltage in this test allows us to see if the heat-sink can cope when extreme loads and overclocks are applied.
With the temps obtained at 4.0 and 4.2GHz I was hopeful of an entry into the elusive 4.4GHz club. Alas it was not to be as the cooler let a core stray over the cut off point we set for testing of 90 degrees.
It's holy trinity time chaps. Performance, looks and noise is what matters when we assess a cooler (ease of fitting is also a factor, but that messes up the "trinity thing").
Looking at performance first it's easy to see that at both 4.0 and 4.2GHz the K2 is sitting on the shirt tails of the big boys. What surprised me though was that it wasn't a lot closer to them. After all it has the right ingredients with 8x6mm heat pipes, Nickel plated copper contact plate and twin Aluminium fin stacks. Being roughly the same dimensions and set up as both the D14 and the Silver arrow, the K2 should really be posting temps very much on a par with them. It is however consistently 4-5 degrees warmer. Even more surprisingly it's also bettered by the NZXT Havik 140 at 4.2GHz. At 4.4 GHz the K2 falls by the way side, no longer able to keep up with the big boys.
Things are slightly improved when we appraise the looks of the K2. The split frame fans with soft rubber coating are some of the nicest looking fans i've seen. Stunning though the performance of the D14 is I don't think anyone out there can honestly say they find the "prosthetic arm" pinky beige they use for their cowlings anything remotely close to attractive. Perhaps Noctua thought that combining it with "Poo brown" would make it look better? Who knows, but I don't think so. Unfortunately the K2 is still up against the Silver Arrow, and although it perhaps pips it to the post in the looks steaks, there's not a lot in it.
Where the K2 really does excel is in the noise department. for such a large cooler it is remarkably quiet. This is perhaps in no small part down to the low rpm of the fans (this might also account for the lower performance to some degree). Not silent, but then nothing that moves truly is, I was actually quite amazed at how little noise the fans made even at the 12volts we test at.
Fitting the K2 is a simple affair, once you've managed to read the microfilm instructions. The fans clip on easily and the whole affair is accomplished in 10 mins or so with no bleeding or swearing which is always good.
At £55 the K2 plonks itself straight into enemy territory. Sure it has the looks, and is quiet but in my eyes that's not enough to make up for the slightly below par performance when compared to it's immediate competition. The K2 isn't a bad cooler, it's just that there are better options available. If you want great looks and quiet operation it's a valid option. If you want outright performance then look elsewhere.
Thanks to OCUK for the Alpenfohn K2, you can discuss your thoughts on this review in the OC3D Forums.