Cooler Testbench Upgrade

Well we are at the dawn of change here at HL, at least in the area of cooling reviews. The HL Cooling Testbench has had a major upgrade and I am glad to be a part of this progress. This is not a new idea, in fact we based this on the method that Intel lists in one of it's P4 Guides. We will be using this method to offer better comparison results among CPU coolers.

I have learned a lot in the past couple years and I will never stop learning. Fortunately I am surrounded by people of wisdom, who I consider to be truly experts in their own specific fields. I have had to seek advise and information from many different people in order to understand whats going on. Now is the time that I will try to share some of what I learned, in fairly basic terms, so that most enthusiasts that are reading these reviews can understand our new equipment and the terms I will be using in my reviews.

THE UPGRADE:
Now stay with me beyond these first two paragraphs and then come back and read them again. First off, with much appreciated assistance from Andrew Lemont from InnovationCooling, we had a groove cut into the IHS of one of our E6850 C2D processors, per Intel specifications. Andrew set us up with this new equipment and made sure the groove was properly machined in the CPUs IHS.

We had a T-Type thermocouple inserted and affixed in the groove. That thermocouple and a second thermocouple (used to monitor the ambient temperature) are plugged into an Omega Microprocessor Thermometer to display CPU and ambient temperatures during testing.



Now for those that understood all that, you are saying, "Move along!" but I am guessing the average reader thinks that was pretty much GREEK (and that is OK). So here we go with some explanations/definitions/clarifications...

IHS (Integrated Heat Spreader)
This is simply the piece of metal (mostly copper with a zinc coating to help prevent corrosion) that is visible on top of the processor. The processor cores actually sit underneath the IHS. The IHS helps distribute the heat and also helps protect the cores. Protected from what? Well, my guess would be "USER ERROR" . The cores are more fragile than the IHS and too much weight or uneven pressure on the cores during cooler installation can permanently damage them. If this happens the processor becomes a paperweight and the computer doesn't boot until you dish out the dough for a new one. So it seems one of the reasons the chip makers added the IHS was to saving us from ourselves (and save themselves from unethical returns). [SPECIAL NOTE: There are many other good reasons for the IHS, including having a consistent, uniform size base so that coolers can be used on multiple CPUs that might not have the same number of cores or cores in the same locations.]

THERMOCOUPLES



These are simply two small wires made from different metals. They are typically side by side but not in contact except for at the very end of the wires. Without going into all of the technical mumbo jumbo, there is a small bead of solder placed where these two wires ends are exposed (pictured above is a close-up of a T-type without the solder bead). The other end of the wires are attached to a device. As the temperature changes, the device is able to detect a change in voltage based on temperature. The device converts that change in voltage to an actual temperature, which is displayed digitally on the device. To the non tech geeks I will repeat: "BLAH BLAH BLAH..." ...Basically, the device is able read the temperature at the solder bead and just believe me, it works !



In our case, the other end of our thermocouples are attached to plugs. They plug into our Omega Microprocessor Thermometer. It sounds fancy but it does tell us the temperature of the beads at the end of the thermocouples (pictured above is the K-type, we use T-type thermocouples). Our device can give us reading in Celsius or Fahrenheit to the 0.1 degree. It also calculates the difference ("delta temperature") between the two thermocouple readings. On a final note, there are several types of thermocouples, basically the difference is the metal combinations that the wires are made of. Our device is compatible with J, K and T type thermocouples, but we use T-type for our testings. It happens to be the thinnest wire, in general, of these three types and fits very well in the IHS groove. You can read more on thermocouples here.

METHOD CHANGE



Our methods for cooling reviews is changing because of this new hardware (including our Omega Microprocessor Thermometer pictured above). We have several coolers being tested currently and an article on our equipment and procedures coming in the near future. Previously we were reliant on temperature monitoring software like Everest, Core Temp and the like. During testing we recorded our ambient temperatures with a basic room thermometer. This is not a horrible way to do things, and it was all we had at the time. We simply had to account for a much larger margin of error.

Now we are able to monitor the ambient and CPU temperatures continually, with more accuracy and, at the same time, get the delta temps. Now our margin of error is much less. We are able to establish how well each cooler performs compared to the ambient temperature.


INITIAL SPEEDBUMPS



During initial setup we did go off the beaten path just a little bit in order to get everything setup to our satisfaction. Intel recommends leaving the thermocouple wire on top of the CPU bracket as seen here in the picture above. But as you can see we had a little hiccup and ended up with a pinched wire. This is a NO-NO when it comes to thermocouples and we had to improvise. Improvise meaning, out comes the bracket, break out the dremel and make some room for our wire.



Here are the before and after pictures of our CPU bracket. The minor modification with a dremel cleared the way for the wire to exit the groove without concern of being pinched. These brackets fit each processor just slightly different on each mobo and we just ended up with bad luck here. The modification may not even have been needed on another setup. In addition, we found that we were then able to run the thermocouple right below the bracket and not take a chance with it interfering with any of our coolers during testing. We just couldn't take the chance of running the wire on top of the bracket like Intel suggested in their guidelines.

So after placing a new thermocouple in the groove and securing it with some top-notch Loctite adhesive we decided to lap the CPU. From the picture of our CPU you can see that it wasn't very smooth. The IHS had plenty of wear and tear and the scratches were plainly visible. This doesn't make for a good smooth testing surface. So we started sanding. We started with a 200 grit sandpaper which took our thin damaged coat of nickle off the top. We then slowly worked our way up to a 1500 grit paper for a smooth finish. We could have gone even higher in grit to give us a near mirror like finish but we ended up with a finish that was about average in comparison to most cooler bases (and no visible imperfections). The thermal grease will take care of the rest.

IN CONCLUSION:
Hopefully I haven't bored you to tears and hopefully you also learned something today. Keep an eye out for the complete article on our new HL Cooling Methodology as well as the advanced cooler reviews that will be released fairly soon...

EDIT: Please understand, this new setup is used to more accurately compare coolers, NOT more accurately measure the actual temperature of CPU cores. This setup does slightly decrease the cooling ability of the CPU itself because we did cut a small groove in the IHS that sits on top of it. However, getting more accurate temperatures (to the 0.1 degree), and using the same surface for each cooler, will tell us, with better accuracy, which coolers perform better.