Testing the Mass-Air heatsink system

Testing the new "Mass-Air" heatsink system

The "Mass-Air" heatsink system consists of a high performance Alpha heatsink, a custom formed aluminum air duct, and two mounting screws with preload springs.
		For this test a ATI Radeon 9700 Pro video card will be used. The small stock heatsink uses a high-speed fan for cooling. Although the heatsink works ok, the fan is too noisy for HTPC use.
To remove the stock heatsink, detach the hold-down pins. The pins consist of two piece plastic parts, a outer bullet-nose step peg and a inner locking pin. To detach the pins, pull the inner pin out as shown above. After both locking pins are pulled up you can use a small screwdriver to carefully push the stepped peg out from the bottom side of card. Now you can lift the heatsink off the card.
		With the heatsink off, clean the processor chip on video card with isopropyl alcohol. Some of the thermal pad may still be stuck to the chip.
The plate around the chip is to help support the heatsink and does not transfer much heat. Most of the heat is transferred from the top of chip to the bottom of heatsink. The gap between the heatsink and chip is .002". A adequate layer of heatsink compound Artic Silver or a thermal pad must be used on top of chip. Do not apply thermal compound to the support plate as this will increase the distance between chip and heatsink making heat transfer less effective..
		The high performance Alpha heatsink uses a copper heat spreader to distribute the heat evenly into the aluminum fins. The fins are very thin with wide spacing between each fin. This decreases the pressure drop across heatsink and allows for high volume airflow.
The heatsink is held in place by two pre-load screws. Each screw has a nylon washer to protect the backside of circuit board. The precision coil springs apply equal pressure to the chip support and allow for expansion and contraction of the heatsink. To set preload, simply tighten the locknuts until the end of screw is equal to the top of nut.
		Heatsink installed on card and ready to mount into computer. The heatsink and air duct clear all components on the card.
The large air duct allows for a unrestricted flow of air across heatsink. The case must have negative back pressure for this system to work. Negative back pressure can be achieved by using exhaust fans to blow hot air out of case. Cool air is drawn in though the intake ducts. If intake fans are used, make sure they are smaller or flow less than the exhaust fans.
		Mass-Air heatsink system installed in case with the air intake duct. The large heatsink and air duct occupy the PCI slot adjacent to the video card.

Test System:

Case: The Heatsink Case
Power Supply: 2U 350 watt
Motherboard: Asus P4T533
CPU: Pentium 4 2.26MHz
CPU heatsink: Alpha PAL8942 with Sanyo Denki 80x15mm fan
RAM: 256MB, RIMM 4200, 32-bit RAMBUS
Video Card: ATI Radeon 9700 Pro
Sound Card: M-Audio Audiophile 2496
DVD Drive: Pioneer DVD-106S
Hard Drive: Maxtor Diamond Max Plus 60GB

Testing Parameters:

I ran each heatsink for one hour to stabilize temperatures. Case fans were connected to a automatic speed controller which adjusts fan speed based on temperature at the sensor. The controller sensor was placed in front of case fans to monitor the air exhausting from case and the air above nearby CPU. To monitor the actual graphics processor chip temperature, I placed a sensor on the backside of video card in the center of chip location. To measure the internal case temp, a sensor was placed above the motherboard between the CPU and face plate. The MB is equipped with a built-in temperature sensor and another sensor is built into the CPU. Digital temp sensor probes were placed inside the power supply and outside of case to measure the ambient air. I used Motherboard Monitor 5 for reading the fan speed and temperatures. For testing full load conditions, I used Hot CPU Tester and Motocross Madness 2. I found running Hot CPU Tester generated the highest temps all around, so I used that test in my results.

Results:

Comments:

The Mass-Air Heatsink system not only reduced GPU temps slightly, but also reduced MB, CPU, and Case temps significantly. This was primarily due to the added airflow across video card. The stock ATI heatsink/fan tends to re-circulate hot air from around the card. Having constant airflow over the card allows the heat to be exhausted through the case fans which lowers all internal temps.

The linear flow of air across the heatsink fins on the Mass-Air does a good job of extracting the heat from the GPU. I tested the heatsink without the air duct in place and the GPU temps immediately rose higher. Other passive heatsink systems on the market do not introduce airflow across the fins, this greatly reduces their effectiveness.

Another benefit of lower overall temps is that the case fans ran at slower speeds reducing noise. At idle, with the Mass-Air HS, the case fans were only running at 1520 RPM. The fans are practically inaudible at that speed. The fan speed was being controlled automatically by the Fan Speed Controller.


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Testing the new "Mass-Air" heatsink system

Test System:

Testing Parameters:

Results:

Comments: