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TEST METHODOLOGY
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Our old modified LX-6A19 (D8000) case from Cool Cases became our test
system housing.
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Our first test procedure is an in-system test designed to determine the card's
power consumption, and whether the card is capable of being adequately cooled
in a low-noise system. By adequately cooled, we mean cooled well
enough so that no misbehavior related to thermal overload is exhibited. Thermal
misbehavior in a graphics card can show up in a variety of ways, including...
- Sudden system shutdown or reboot without warning.
- Jaggies and other visual artifacts on the screen.
- Motion slowing and/or screen freezing.
Any of these misbehaviors are annoying at best and dangerous at worst - dangerous
to the health and lifespan of the graphics card, and sometimes to the system
OS.
Test Platform
Measurement and Analysis Tools
- CPUBurn
processor stress software
- ATITool
v0.26
artifact scanner to stress the GPU.
- RTHDRIBL
as an alternate tool for stressing the GPU.
- SpeedFan
version 4.33 to show CPU and GPU temperature.
- Seasonic
Power Angel AC power meter, used to measure the power consumption
of the system.
- A custom-built variable DC power supply to power the system fan.
System airflow is quite good, allowing the CPU and system fans to run at close
to inaudible speeds without compromising system cooling. The intake is about
the size of a 120mm fan. The only restriction is an air filter. A much more
restrictive cover for the filter was removed because it impeded the airflow
too much.
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The one and only intake...
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...and the same view, with the bezel removed.
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There is only one point of exhaust: The Nexus 120mm case fan which will be
run at a number of different speeds. The 80mm fan in the Neo HE power supply
was taken out of the picture by using a custom-built duct to ensure that the
fan never ramped up. The amount of airflow through the system can be controlled
by adjusting the speed of the case fan, thereby giving us a way of controlling
how difficult the thermal environment inside the case is.
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A fresh air duct isolates the power supply from the rest of the system.
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Only one possible points of exhaust: The orange case fan.
The fan in the power supply draws its air from a duct that does not interact
with the rest of the system airflow.
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The airflow in our test rig is typical of an ATX case. Air flows in through
the intake near the bottom of the front panel, and is pulled up to the top rear
corner. Most of this air will bypass the expansion cards altogether, but a small
amount will be pulled across the rear of the card as it is pulled towards the
CPU heatsink and the case fan. All of the air will exit the case via the exhaust
fan.
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The air will flow from the lower right to the upper left, drawing a small
amount of air across the VGA card.
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Testing was conducted initially with the system fan at 12V with
the system idle, and running two instances of CPUBurn. Then ATITool's artifact
scanner was run in conjunction with two instances of CPUBurn to generate as much
heat and power draw as possible from both the CPU and GPU. During this portion
of testing the system fan voltage was slowly turned down to see what thermal
consequences arose from limiting the amount of system airflow provided.
SpeedFan and was used to measure CPU and GPU temperature, and the results were
recorded after the GPU temperature stabilized. After the final, most demanding
test with the system fan running at 7V, ATITool was left running for 30 minutes
and then replaced by RTHDRIBL for 30 minutes after that. Throughout this step
we watched the screen for visual artifacts that might indicate overheating.
If either ATITool or RTHDRIBL detected artifacts in this minimum airflow and
maximum heat test situation, the card would be retested for artifacts with the
system fan at 9V and 12V to determine whether system airflow was a contributing
factor to failure.
The card is determined to have passed our testing if it managed to survive
the duration of testing without ATITool or RTHDRIBL detecting any artifacts.
AC system power consumption was measured from the outlet using a Seasonic
Power Angel and actual DC power use was estimated/extrapolated using the efficiency
figures deduced from our Antec
Neo HE 430 review: 67% at 62W, 76% at 85W, 76% at 119W, 79% at 190W
(all wattages are AC).
During testing the ambient temperature was 21°C and the noise level was
approximately 18 dBA.
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