First Impressions


Upon first inspection one is left with the feeling that this cooler was originally a tower design heatsink that had the heatpipes accidentally bent 90 degrees. Essentially that is what down draft style CPU coolers such as the Igloo are. In this case however there is only support coming from one side, so instead of looking like a strange square it has a more "C"-like design. This is where its design starts to run amok, for unlike other similarly designed coolers the opposite side of the baseplate and fin assembly is not reinforced. This means that not only is the full weight of the unit being suspended by the heatpipes but the constant torque and vibrations from the fans are also being absorbed by the heatpipes. This makes for a unit that does flex alot and does make its long term viability a bit of a question mark.

There are pros and cons to down draft coolers. On of the major cons is that hot air is funneled down and over the cpu itself which can increase heat but and the same time, this deign ensures air movement to cool of the MOSFET and hot chipsets on the motherboard. Another relatively minor pro is that down draft coolers are usually of a lower profile than tower designs. This can be a major issue or a non issue, it all depends on what case you are intending to mount this cooler in. Someone interested in a quiet HTPC will have different priorities than someone who has a full tower case.

As noted, since the hot air is being blown down and across the CPU base this cooler’s biggest weakness is its own design. As thermal loads increase more and more of the cooler's potential will be used in cooling the heatsink's base plate rather than the CPU. Of course, one could argue that if properly implemented this “hot” air can be recycled and actually help cool the cooler's base plate. After all, the more air movement the more time for heat to be radiated / moved away from the CPU. To a certain extent this is true, but it is true only as long as the air moving over cooler base is cooler than the CPU. In a nutshell down draft CPU coolers can be more than adequate solutions just as long as the thermal load is low enough or the design is efficient enough, or even if the cooler’s fan(s) can physically move enough air. This is a known issue with this style of cooler and there are a few partial solutions to it.


The easiest solution to this known issue is allowing the base of the cooler to act like a small heatsink. GlacialTech’s engineers did not make the base of the cooler flat, rather they designed small fins to trap and recycle the air current created by its two fans. These small fins significantly increase the base’s cooling surface area and all this extra space goes a long way to keeping the cooler from becoming its own enemy.


Another partial fix is more of a "brute force" option: add more heatpipes. The more heatpipes, the more efficient the cooler and the more likely it is to perform well at higher thermal loads. Unfortunately, and unlike some other down draft coolers, the Igloo 5750 only has four short 6mm diameter heatpipes coming from only one side of the base plate. If GlacialTech had made the 5750 a “double 4” style cooler or even had designed it with eight of these short “half length” heatpipes this could have helped with this thermal load problem. Then again maybe 4 heatpipes was found to be the optimal solution.


Still another solution avaible to enginers in combating down draft coolers thermal inefficiency is to give the cooler a large enough fan, thus enabling enough air movement to make this whole potential issue a moot point. After all, when finesse fails brute force usually doesn’t. There really is no such thing as overkill when it comes to cooling today’s CPU’s or as my grandpa used to say “when in doubt get a BIGGER hammer”. In the case of the Igloo 5750 Silent model, the fans used are 92x92x20mm meaning that they are not only smaller than most down draft’s 120mm fans they are also a lower profile. This means that they not only have to spin faster than 120mm fans to move the same amount of air, they even have to spin faster than normal full height 92x92x25mm fans. This coupled with the fact that this particular 5750 is marketed as having “silent” fans that rotate at a relatively slow 1400rpm does not instill confidence in the potential performance of this down draft cooler. However, it does have two of these small fans in a push - pull configuration so it does have some potential to outperform a single full height 92mm fan. Later in the review we will see just how good (or bad) these small fans are.

Please note: A “push – pull” configuration is where one fan (on one side of the heatsink) pushes air through the fins and over the heatpipes, and the other fan (conveniently located on the opposite side) “pulls” the now hotter and heavier air away from the cooler. In this instance the air is then blown down and over the coolers base plate.

On the positive side the fans themselves are securely mounted to the partially enclosed fin array with standard screws. This makes for a very secure mounting and does make swapping out a dead fan very easy. The down side to this style of mounting does mean that all the torque and vibrations from the fans are transferred directly to the heatpipes that are the sole means of support. We will talk about the fans in greater detail later in this review but for right now it is suffice to say that constant flexing and vibrations from these fans can be considered a major flaw in this units design, which could have been easily overcome with the inclusion of some sort of vibration dampening agent (e.g. springs or rubber washers or even rubber mounts instead of screws).


As you can see, the cooling fins are fully enclosed on all sides by either metal shrouds. This does have the admirable advantage of protecting them from knocks and bangs. On the down side, since they are enclosed their cooling potential is actually slightly lowered and static pressure that the fans have to overcome is actually increased. As with all things engineering related, this is the end result of a series of compromises. The metal enclosure does cause the fans to work harder, but it also allows for a solid mounting surface for the fans and it gives added “Bling” to an otherwise average looking cooler. Overall, I think that GlacialTech made the right choice.


One thing worth mentioning is that while this can be considered “shorter” than some tower coolers it is by no means “short”. In fact it is about twice as high as the stock Intel 775 cooler. Its height was by no means an issue and in fact in a CoolerMaster CM690, we were able to keep the two door mounted 120mm fans on and still close the case door with room to spare. However, the Igloo is a bit too high to fit into most HTPC cases.


Also on the positive side the Igloo 5750 came with its own Thermal Interface Material (aka "TIM"). It came pre-applied and was a grease base TIM and not the cheaper (and older) wax pad style. However, as we will show later, one should really invest an additional few dollars and apply a good after market TIM like Arctic Cooling MX-2 or Arctic Silver AS5.


Here you can see that the base is even and but does show some major tooling marks. It should have been polished a lot more before leaving the factory. It is not the worst polished base we have seen but it is not the best either. Overall, the level of quality at this price point is below average.