Date:
Monday , April 13, 2009
Author:
Marc Adams
Editor:
Kyle Bennett
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Xpressar Refrigeration System & Xaser Chassis

Thermaltake, a leading manufacturer of cases for PC enthusiasts, is here to show us their cooler side. The Xpressar Refrigeration system is Thermaltake's first attempt in serious phase change cooling. This is a "micro" refrigeration system aimed at silence rather than balls out 24/7 overclocking.

Introduction

Today at the [H] we are going to do things a little bit different. Rather than look at the newest air cooled heat sink and its attempt to dethrone the awesome might of Thermalright’s TRUE Copper, we are going to look at a phase change unit coupled with an enthusiast case for a true all-in-one solution. Astute cooling enthusiasts are probably wondering if I have forgotten that heat pipes are a form of phase change cooling. You are absolutely correct but they are a form of passive phase change cooling. Heat pipes utilize a special fluid that boils at very low temps and it is this fluid which provides the mechanism for cooling. Today we are looking at something much, much cooler. The Xpressar Micro Refrigeration Cooling System from Thermaltake is designed to reach temperatures low enough to cool any CPU on the market to extremely low temperatures, below anything that a normal heat pipe situation could produce.

Ordinarily, when someone wants to make the jump into serious phase change cooling there is a lot of prep work that needs to be done. Details like cooling power, condensation, insulation, dew point, and ambient temperature make the task increasingly difficult for newcomers to enjoy the cooling potential of phase change cooling. Simply put, phase change cooling is not something you do half-assed if you intend to be using your equipment for more than a couple of days.

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System Setup

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Please take note we are utilizing a new motherboard and RAM for this testing. This XFX motherboard allows us to adjust CPU fan speed on a much finer scale than allowed by the ASUS board we had been using before. Prior to this article, tests were conducted to ensure temperature testing would remain consistent. Using the same CPU with the TRUE at the same voltage and speed settings resulted in the same temperatures at idle and load.

Test Methods

CPU

When we concluded the first roundup of CPU heat sinks Kyle and I both came to the same conclusion. Software monitoring just isn't going to cut it. We need to step it up the [H]ard way. That is just what we did. We reached out to Intel about using a hardware monitor drilled into the IHS to measure the CPU temperature and wouldn't you know it, this is the exact way Intel tests their own chips. Now we knew we were on the right path. A few weeks later and a little planning along with some specifications and we were able to do it just like Intel does.

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Temperatures for the CPU will be measured using a Sperry Digital 4 Point thermometer. We can also monitor the temperature of the North Bridge through the Asus Probe application. This will let us know if the heat sink provides any additional cooling to other components. Something that becomes more and more important as you overclock.

Now you may be asking why we didn’t just use a quad core CPU and continue monitoring temperatures through software. Take a look at this table. These measurements were recorded using the Intel stock cooler with the CPU at default settings. Core-Temp reports the individual temperature from each core.

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With large discrepancies and variations between programs, this is why we chose hardware monitoring.

GPU

For this article the GPU will be kept at stock speed to keep any excess heat away from the CPU that could impact the results. In 2D mode the 7900GTX under clocks its core to 275MHz which creates very little heat and allows the fan to run at inaudible levels.

Thermal Paste

Noctua's NT-H1 thermal paste was selected as the paste of choice for a few key reasons. Firstly, the thermal paste has been shown to provide excellent thermal conductivity allowing the heat sinks to better do their job. Secondly, there is no observed curing time. That is, performance does not get any better over time. Any curing time could have introduced variables into the equation causing at best dubious results and at worst unreliable ones. Lastly, because we have a special CPU on our hands it requires a compound that is more viscous so not to seep into the channel and run off.

Temperatures

Ambient temperature will be kept at 25C for the duration of the tests and measured with a MicroTemp EXP non-contact infrared thermometer and cross referenced with the Sperry Digital 4 Point thermometer. Any variance greater then 0.2C will halt the testing until temperatures return within spec for fifteen minutes.

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Idle

Idle temperatures will be recorded after a fifteen minute period of inactivity. Any fluctuation during the last sixty seconds will reset the timer for an additional five minutes.

Load

Load temperatures will be recorded after a fifteen minute period of 100% load. To obtain this we will be using Prime95 v25.3. We have previously used Intel's Thermal Analysis Tool (TAT) to create a load on the CPU but this application is not designed for quad-core CPUs. Any fluctuation during the last sixty seconds will reset the timer for an additional five minutes.

Sound

Sound levels will be measured with a Reliability Direct AR824 sound meter from a distance of four feet away. With everything turned off and the room completely silent the meter registered a sound level of 38dB(A). This is a very quiet room where a simple pin drop could be heard. All sound measurements are recorded in the very late evening to further reduce any ambient noise.