Cooler Master is a name well known not only to hardware enthusiasts, but also to the average joe who has cracked open a case or two before with an AMD processor running inside, as CM supplied AMD with CPU coolers during the Athlon XP era.

                                             The Cooler Master name is no accident.
 

It comes to no surprise then that Cooler Master (CM from here onwards) is still going strong with new and innovative solutions for computer related items ranging from power supplies, chassis and of course, cooling. In particular, CM has always maintained a strong presence in the CPU cooling front, and the most recent product available for this is the Geminii S CPU heatsink.

                                             The Geminii S showing its best profile

This heatsink and fan combination brings forward a new concept for computer cooling – while it is primarily a processor fan, its construction makes it able to cool the surrounding areas of the motherboard as well as the processor. This is more often than not the MOSFETS and the capacitors surrounding the CPU socket, which are often neglected by system builders and modders alike in their quest to bring down CPU temperatures as much as possible.

It can actually almost serve as a system fan, but this is not accurate, because the capability of this heatsink to cool is reliant on the fan configuration installed, as well as independent system fans that bring in cooling air from outside of the case. The Geminii S is capable of accepting either a single 120mm fan or two besides each other. When two 120mm fans are installed, the excess airflow gets directed towards the surrounding areas, most notably the RAM sticks (on a standard-layout motherboard), the CPU – power components, and perhaps the northbridge.

                                             The protruding fins slide neatly over the RAM slots.

The heatsink itself looks like an oversized heatsink+fan combination, not unusual in itself, but with appreciable overhangs attached on both sides – which is. The overhanging fins accommodate the 120mm bulk of the fan, and are trimmed down to the size of the CPU socket. This serves as additional cooling area for the CPU, and is better implemented by the heatpipes running through the fins. These also coincidentally overhang the RAM slots – thus making use of any additional overflow to cool these slots.

Since motherboard chipsets and power components on the board have steadily been getting hotter due to performance increases and the like, this is a good move for CM, and perhaps a prod for other cooler manufacturers to take more consideration for motherboard components.

                                             Heatpipes plus a lot of fins equals cooling efficiency.

The heatsink element directly exposed to the processor, plus the heatpipes are of copper construction, while the very thin fins are made of aluminum. There is a total of five medium diameter heatpipes,plus a lot of fins, each of them very delicate looking – and each of them comprising of more cooling area than your average early-2000 heatsink. The package includes the following items:

• Assembly & installation guide written in several languages  
• Fastening frame for LGA775 mainboards
• Cooler Master thermal grease
• Back-plate for Socket 939/AM2
• Screws
• Fastening frame for Socket 939/AM2 mainboards
• Rubber pads, spacers and nuts with a key

The package in other words is compatible with all the major chip types available, with the exception of some older CPUs. It also includes brackets that let the user adjust for the number of fans to be attached. Also note that we get a CM – branded 9 bladed fan, which performed silently and effectively on our Core2 6600 test bench.

                                             Not shown are the additional screws, spacers and extension brackets.

It is not as heavy as expected given its bulk, which is a good design testament for the CM guys, and helps alleviate worries of cracked motherboards or straining connectors. Fan speed is from 1000 to 2000rpm, adjustable through a third-party application or hardware controller. Fan noise rating of 17-21 dBA is borne out in our testing, this being aided by the relatively slow 120mm fan.

                                              Powder coated and smooth,it is a unique fan on a unique heatsink.

Test fitting on other motherboards around our lab went well, with motherboards ranging from an old Athlon socket 939 (although not mentioned as being compatible) to our test Core2 board all able to accommodate the heatsink and fan combination. Cooling capability is above average compared to other coolers in its price range, improving the temperature of the CPU by 5-8 degrees Celcius on average, considering both idle and load temperatures. Testing was done by running Prime 95 for 2 hours on both the stock Intel fan and the Geminii S.

                                             Engine block sold separately.

Make sure you measure out your motherboard before purchasing though – although it is designed to fit in the majority of boards, one can never know if the majority includes your own motherboard. The heatsink itself can be outfitted with either a single 120mm fan or two 92 or 80mm fans. All in all, a good looking and excellent performing heatsink and fan combination that cools both the CPU and motherboard, from the veteran cooling company, Cooler Master.

Look forward to an in-depth review in our January issue of HWM. More pics after the break.

                                             A good view of the pipe and fin symmetry.

                                              Coincidentally, the same as our test bench.