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TEST RESULTS
#1 - Baseline, with Integrated Graphics: First, here are the results of our baseline results of the system with just its integrated graphics, without
a discrete video card. We'll also need the power consumption reading
during CPUBurn to estimate the actual power draw of each individual card later.
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VGA Test Bed: Baseline Results
(no discrete graphics card installed)
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System State
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CPU Temp
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System Power
|
|
AC
|
DC (Est.)
|
|
Idle
|
22°C
|
73W
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Unknown
|
|
CPUBurn
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39°C
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144W
|
115W
|
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Ambient temperature: 21°C, noise level: 20 dBA@1m
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#2 - Radeon HD 3850: The fan was very loud at bootup, but it quickly
throttled down to the point where it was below or at the ambient noise level
of our test system. Oddly, we could not coax the fan to spin up again, whether
automatically by stressing the GPU or toying with ATITool to do so manually.
Still, the cooler surprised us by keeping the GPU core temperature
at 89°C during extended load without artifacting or any other instability. Anything under 90°C
is acceptable, and the fact that it was inaudible amazed us, especially since
we were not impressed initially with the stock cooler design. Power consumption
was very low, indicating excellent efficiency — there wasn't a lot
of heat to dissipate.
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VGA Test Bed: Radeon HD 3850
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System State
|
GPU
Temp
|
CPU
Temp
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System Power
|
|
AC
|
DC (Est.)
|
|
Idle
|
45°C
|
23°C
|
88W
|
66W
|
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CPUBurn
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51°C
|
41°C
|
157W
|
126W
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CPUBurn + ATITool
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89°C
|
42°C
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208W
|
170W
|
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Ambient temperature: 21°C, noise level: 20 dBA@1m
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The fan problem may be specific to our test sample, as we know
of many users who are successfully controlling the fan on their HD 3850s. Actually
we don't even regard it as a problem, since cooling was fine at the speed the fan was
stuck at.
#3 - Palit Radeon HD 3870: The fan control was automatic, but could also be over-ridden
with ATITool. Setting the fan between 0% and 30% resulted in the
same fan speed — what the card automatically used when idle. When stressed,
the fan vacillated up and down between 30% and 50%, trying to keep the GPU temperature
at around 90°C.
When we set the fan speed manually to stay at 30%, it was
not enough to keep the card cool. Artifacts appeared in ATITool as the GPU temperature
rocketed past 100°C. 40% seemed to be the sweet spot, keeping the GPU core
at 90°C with only a small increase in measurable noise (22 dBA). Incidentally,
90°C is how well our X1950XTX VGA heatsink test card's stock cooler performs,
but with the fan speed at 43% and a noise level of 28 dBA.
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VGA Test Bed: Palit Radeon HD 3870
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|
System State
|
Fan Speed
|
Noise Level
|
GPU
Temp
|
CPU
Temp
|
System Power
|
|
AC
|
DC (Est.)
|
|
Idle
|
30%
|
21 dBA
|
56°C
|
23°C
|
94W
|
71W
|
|
CPUBurn
|
30%
|
21 dBA
|
57°C
|
41°C
|
164W
|
132W
|
|
CPUBurn + ATITool
|
30%
|
21 dBA
|
102°C*
|
42°C
|
228W
|
187W
|
|
CPUBurn + ATITool
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40%
|
22 dBA
|
90°C
|
42°C
|
228W
|
187W
|
|
CPUBurn + ATITool
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50%
|
26 dBA
|
73°C
|
42°C
|
225W
|
184W
|
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Ambient temperature: 20°C, noise level: 20 dBA@1m
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The noise signature of the fan was poor. At 30% the overall noise
level was low, but the fan had a slight ticking and a low-pitched hum. At 40% fan
speed it registered 1dBA higher but the pitch of the sound also increased. At
50%, the ticking went away but the noise level became intolerable, thanks to
higher air turbulence and the motor running like a small vacuum cleaner.
40% is the minimum we would run the fan at, but at that speed, its 22 dBA noise
reading is deceptive as it's abrasive rather than smooth. It's too bad that ATI did not keep the heatpipe from the X1950XTX heatsink design or
increased the size and area of the fins and employed a fan with better acoustical
properties.
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