UH X2 "slotket" cooler construction article

By John Bogush 03/12/2000

I wonder how many folks out there right now are pursuing their overclocking endeavors with their slotketed CPU but suffering along with the availability of only a single usable DIMM slot due to the inadequate choices of effective and space conscience processor heatsink cooling solutions. It is not a new problem relatively speaking but the truth is sacrificing the first few DIMM slots on most motherboards when trying to cool a slotket adapter mounted processor has mostly become an accepted practice. Sure ALPHA, GlobalWIN and a few other companies offer decent cooling solutions but they just don't fit most motherboards without causing interference problems with at least one or two available DIMM slots. To make matters worse not only do you suffer from limited memory capacity but very often placing your memory modules in any slot out of the motherboard manual's recommended order can cause stability problems and intermittent errors.

I've got an idea...

After studying a few of the more popular and better performing heatsinks on the market I decided that I wanted to search out a solution that would not only allow full use of all a motherboard's memory slots but cool as well or better than any conventional heatsink presently available. Designing and constructing a new heatsink was out of the question as far as I was concerned. I just didn't think that all that effort was necessary given the fact that a few heatsinks I already had in mind performed very well but ventilating them in a space conscience manner was the problem. I quickly ruled out conventional axial flow fans such as we are all familiar with and after looking around my shop I noticed a pair of Nidec Gamma 28 blowers sitting in the corner that PLYCON Computers had sent me waiting on a then unknown future project.

A Gamma blower is...

For those of you that are not familiar with the Nidec line of Gamma blowers let me fill you in. These are centrifugal blowers also sometimes referred to as "squirrel cage" fans. I first became familiar with the nifty line of Gamma blowers by Nidec when searching for a way to help cool my brand new Voodoo card a couple of years ago. Way back then 3Dfx was just rocking the gaming world with their introduction of the first Voodoo 3D graphics add-on card. The first thing I realized was those suckers ran hot and some extra fresh air was in order. Since space was pretty limited in my system case with all the expansion slots already filled with one type of card or another I decided I needed to find some type of fan that could direct a high velocity stream of air from several inches away directly onto my Voodoo card's chipset. After flipping through various electronics supply catalogs I came upon the Gamma blowers. Available in five different sizes from 51mm through 120mm I decided on the Gamma 28 which measured 76mm X 76mm X 30mm and moved 9 cubic feet of air a minute (cfm). After receiving that first Gamma blower all I had to do was add a conventional power connector and attach the blower to the interior of my system case with double-sided 3M foam tape so that the blower's output was directed onto my Voodoo card sitting about 6 inches away. The Gamma 28 worked so well it actually ended up catching on with various postings and articles surfacing on the Internet which lead me to the discovery that I was not the only one to stumble upon this little treasure.

Well I knew that a Gamma blower was again going to be the answer to this new cooling challenge. After carefully measuring and fitting two Gamma blowers together in various fashions I settled upon the GlobalWIN FDP-32 heatsink as the foundation upon which to construct my new creation. It just so happened that the FDP-32 heatsink was the perfect size to accommodate my twin Gamma 28 blower setup. With a little simple sheet metal work and a few screws I soon had the prototype UH X2 ready for it's first test run. The system was a slotketed Celeron 366 on a SOYO 6BA+III that would happily run 605MHz with the standard GlobalWIN FDP-32 setup that I had been using. Sure enough the system successfully booted and loaded Windows 98 with the UH X2 installed. I decided to see just what my new contraption was capable of so I fired up Prime95 to stress the system and watched the Celeron's internal temperature diode using Motherboard Monitor. I was surprised not only to find that the UH X2 was keeping up with what the FDP-32 could do but it actually allowed my Celeron to run 3c cooler. Though I believe the cooling performance is significant I don't believe it is enough to take a stubborn processor to the next MHz level.

These results were obtained on my heatsink test rig which uses a 40 watt TEC (Peltier element) to simulate the thermal load presented by the typical processor.

The heatsink to be tested is mounted to the hot side of the TEC while the cold side is mounted to a 3/4" block of aluminum and auxiliary heatsink. Basically the TEC is trying to cool the ambient room air via the cold side mounted auxiliary heatsink. This setup presents a considerable thermal load to the heatsink being evaluated. The temperature reported is the lowest temperature obtained as measured from a hole drilled into the center of the aluminum block. The colder the block, the better performing the heatsink being evaluated is.

The UH X2 performs very well compared to a few other popular socket coolers.

A few little observations about the UH X2. First of all although it does allow use of all the memory slots on any motherboard it is fairly tall at 5 7/8". I am pretty sure that it will fit in most popular cases but make sure to measure the available clearance in your system if you decide this project might interest you. Another feature you might have noticed is that even in a dual configuration the Gamma 28s installed in the UH X2 only put out about 18cfm as compared to the 27cfm of the 60mm YS Tech fan that comes standard on the FDP-32. I theorize that the airflow from the Gamma 28s is utilized in a more efficient manner through the fins of the FDP-32 heatsink because of the duct work on the UH X2 allowing it to cool better than the open setup of the standard FDP-32. Now if you are still interested in perhaps constructing a UH X2 cooler for yourself then follow along...

The construction >>

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