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THERMAL & ACOUSTIC TESTING
Thermals and noise comprise the core of most SPCR equipment reviews. Our usual
gamut of software tools were installed:
Other tools:
TEST PROCEDURES
Ambient conditions were 21°C and 19 dBA. The noise sources in the system
and the ways they were controlled are as follows:
1) The two 80mm case fans were controlled by an external variable power
supply for testing convenience.
2) The fan on the CPU cooler was plugged directly into the fan header on
the Asus motherboard, which was set to adjust the fan speed according to CPU
temperature. We know the range is rather narrow (about 65~100% of maximum
speed) but as the fan is a low airflow Nexus, we judged this to be appropriate.
Besides, it's what we've done for previous HTPC case reviews.
3) The fan on the Zalman VF900 cooler on the XFX GeForce GF6800XT video card
was left at 5V throughout the testing. We know from previous experience that
this is good enough cooling under most conditions, and quiet enough not to
be a limitation.
4) The Seagate Momentus 7200.1 100gb notebook drive was used as the main
system drive. It sat atop a piece of foam in the drive cage to simulate elastic
suspension.
5) The Samsung SP2504C 250GB 3.5" drive was used for storage. It was
bolted into the drive cage normally. This gives some idea of how well the
case deals with vibrations from a quiet, medium vibration 3.5" drive.
6) The Seasonic S12-430 was left to fend for itself. Its noise characteristic
are well documented in our review. It's a quiet component whose fan should
not speed up even under full load in this system.
The case fans were the only ones we adjusted directly. They were set to 6V,
9V and 12V, and a full set of tests were conducted at each fan voltage setting.
A. Case Fans at 6V
|
Case Fans @6V: Silverstone GD01 w/ Test System
|
|
System State
|
CPU
|
GPU
|
HDD*
|
AC Power
|
Noise (SPL)
|
|
Idle (Cool'n'Quiet)
|
30°C
|
45°C
|
40°C
|
98W
|
25 dBA@1m
|
|
Idle (No CnQ)
|
33°C
|
45°C
|
40°C
|
114W
|
25 dBA@1m
|
|
2 x CPUBurn
|
68°C
|
51°C
|
42°C
|
187W
|
27 dBA@1m
|
|
2 x CPUBurn +
RTHBRIBL
|
67°C
|
68°C
|
42°C
|
204W
|
27 dBA@1m
|
|
*The hotter of the two HDDs; the other was always
2°C cooler.
|
The overall noise signature at idle was smooth and quiet. Most users would
find it perfectly usable even sitting close to them on a desktop. As a HTPC
on a rack under the TV 5~10 feet away, this noise would be drowned out the instant
the TV was turned on. From up close, some of the vibration from the Samsung
3.5" HDD could be perceived as a low frequency hum, but it was very modest
and inaudible beyond a few feet.
At high loads, the increase in noise was caused by the CPU fan being sped up
by the motherboard's fan controller. The idle fan speed was reportedly 830 RPM;
it increased to 1400 RPM at full load. The 2 dBA@1m increase seems small, but
it was somewhat more audible than the number suggests, because of an increase
in tonality. A suggestion of "whine" became present at the higher
speed. Still, the overall noise was far below the level of any TV, movie or
music program you might listen to on a HTPC, and thus quite acceptable.
The cooling of the CPU was adequate, although it could have been better. The
GPU cooling was very good, as 68°C is a modest peak temperature for a graphics
card.
B. Case Fans at 9V
|
Case Fans @9V: Silverstone GD01 w/ Test System
|
|
System State
|
CPU
|
GPU
|
HDD*
|
AC Power
|
Noise (SPL)
|
|
Idle (Cool'n'Quiet)
|
30°C
|
44°C
|
38°C
|
98W
|
27 dBA@1m
|
|
Idle (No CnQ)
|
32°C
|
44°C
|
38°C
|
114W
|
27 dBA@1m
|
|
2 x CPUBurn
|
60°C
|
48°C
|
40°C
|
187W
|
28 dBA@1m
|
|
2 x CPUBurn +
RTHBRIBL
|
60°C
|
58°C
|
40°C
|
204W
|
28 dBA@1m
|
|
*The hotter of the two HDDs; the other was always
2°C cooler.
|
The noise became louder at this voltage, but it was the increased tonality
(a small peak somewhere in the midrange) that made it more audible. It was still
quiet enough for most people in most HTPC applications. The cooling improved
quite a bit across the board: 7~8°C for the CPU and 10°C for the GPU.
The small drop in HDD temperature suggests greater airflow through the front
vent as well, despite its impedance and distance from the case fans. The increase
in CPU fan speed under load did not result in as much of an audible difference
as before, due to the higher baseline noise at idle.
C. Case Fans at 12V
|
Case Fans @12V: Silverstone GD01 w/ Test System
|
|
System State
|
CPU
|
GPU
|
HDD*
|
AC Power
|
Noise (SPL)
|
|
Idle (Cool'n'Quiet)
|
29°C
|
42°C
|
37°C
|
98W
|
30 dBA@1m
|
|
Idle (No CnQ)
|
32°C
|
42°C
|
37°C
|
114W
|
30 dBA@1m
|
|
2 x CPUBurn
|
58°C
|
47°C
|
38°C
|
185W
|
30 dBA@1m
|
|
2 x CPUBurn +
RTHBRIBL
|
58°C
|
54°C
|
39°C
|
202W
|
30 dBA@1m
|
|
*The hotter of the two HDDs; the other was always
2°C cooler.
|
The slight tonality that appeared at 9V turned into a higher pitched hum that's
very difficult to ignore. This is too loud by SPCR standards. The cooling improved
again, across the board. A surprise was that the GPU temperature dropped another
4°C. Note the slight drop in AC power at high loads; this is probably indicative
of improved VRM efficiency due to improved cooling.
D. With a Ninja Mini
This was a last minute test run done just out of curiosity. Would the Scythe
"Minja" do a better job of cooling the CPU than the nMedia IceTank
in this HTPC?
Ninja Mini in test system with Nexus 92 fan.
The answer to that question is no. The results were so
close to those achieved with the nMedia IceTank that they might as well be a
second test run with the latter (which is why they're not shown in a table here).
We expected better. Why didn't we get better? Possibly because the case did
not "breathe" well enough for the low airflow qualities of the Ninja
Mini to come to the fore, possibly because the fan had to be set up to "suck"
through the fins, rather than blow through them. We didn't have time to explore
the reasons fully or try other fan configurations. In any case, this experiment
showed us that our choice of the IceTank as a cooler for these HTPC reviews
is reasonable. It's a pretty good cooler if it keeps up with the Minja with
the same low airflow fan.
Minja's 115mm height leaves another 7/8" or ~23mm clearance under the
case cover.
ANALYSIS
It should be noted that acoustics requirements for an entertainment PC tend
to be less demanding than for many other types of PCs, simply because music
and movie / TV sountracks help to mask the noise. Please see the page on Acoustics
Around a Media PC in our Cases Reference article for a fuller discussion.
Despite our misgivings about the front vent intake, the GD01 performed acceptably
from a thermal standpoint even with the low airflow of its fans at 6V. The resulting
25 dBA@1m SPL is very good, especially as it includes the contribution from
a hard-mounted 3.5" desktop hard drive. Cooling improved tremendously with
the case fans set to 9V, where the noise began to take on a tonal aspect. For
most SPCR readers, this is about as fast as those fans should spin, but it's
still quiet enough for HTPC duty, where higher ambient noise can be assumed.
The LC17 should perform at least as well, and most likely a touch better due
to the slightly less impeded front air intake path. This comment probably applies
to the non-VFD version of the GD01 as well; the VFD module is a major impedance.
These results were obtained without resorting to an extra 80mm fan on the side
vent close to the CPU. A quiet, smooth fan for intake at that vent could allow
better thermal performance with little cost in noise. It may be worth experimenting
with.
Keep in mind that continuous CPUBurn and RTHDRIBL loading in excess of an hour
is hardly a normal load for a HTPC. None of a HTPC's duties come close to
matching such an extreme load, which can be said to be a true torture test.
In light of this, the thermal performance of the GD01 case with the fans at
6V is very good indeed.
It should also be noted that the CPU, graphics card and motherboard used in
our test system are hotter than we would recommend for use in a HTPC. We used
them precisely because they pose a more extreme thermal load. By today's more
power-efficient standards, all of those components are mediocre, and they can
easily be replaced with components that provide equal or better performance
while running substantially cooler.
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