QMicra from PC Design Lab: SFF Super-sized

Cases|Damping
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THERMAL & ACOUSTIC TESTING

Thermals and noise comprise the core of most SPCR equipment reviews. Two variations of the same system were installed and tested in the QMicra. The base components are listed below. They are the same components used in our recent reviews of Antec NSK3300 and the Lian Li PC-101, so these cases will be used as reference points. Note that different power supplies were used for all of the systems in question. This may well affect noise results.

DFI RS482 Infinity MicroATX motherboard
This new ATI Radeon Express 200 chipset model from DFI has the most flexible and user-adjustable BIOS we've seen on any microATX board, comparable to the best of the full-ATX boards. It allows the CPU core voltage to be manually set without disengaging Cool'n'Quiet, which simply applies the manual voltage adjustment to the various CPU power states. It allowed the X2 4800+ to be undervolted by 0.1V throughout the testing, for very modest power consumption in every load. It has no fans.

AMD Athlon 64 X2 4800+ processor
Not long ago, this was AMD's current second fastest desktop processor, one small step down from the flagship FX-60. This particular dual-core sample has a rated TDP of 85W. Previous testing showed it easily undervolts by 0.1V or more, with resulting power draw at full load of just ~60W at the 2x12V motherboard socket.

Antec Neo HE power supply
One of the quietest power supplies on the market, and the only one with straight-through airflow that we recommend.

OCZ Technology Gold PC4000 2 x 512MB DDR matched dual channel memory.

Samsung SP2504C 250GB SATA 3.5" hard drive
A quiet 3.5" desktop reference. It measures 21~22 dBA@1m.

Other components included:

Gigabyte GV-NX76T256D-RH GeForce 7600 GT video card
A passive midrange video card that is relatively power efficient.

Zalman CNPS9500 CPU HSF
A heavy duty heatsink for a hot processor, this is an effective cooler even undervolted to 5V. It measures 23 dBA@1m.

Windows XP Pro SP2 was installed and fully updated, and our usual gamut of software tools installed:

  • SpeedFan 4.28 for CPU and other hardware monitoring.
  • CPUBurn for processor stress testing.
  • ATI Tool provides a steady high load to the GPU in a reduced window, allowing other tools to be in use at the same time.
  • RivaTuner allows the core temperature of the GPU to be monitored over time.

Other tools:

TEST RESULTS

Ambient conditions were 23°C and 19 dBA. It is summer, and the lab is a few degrees warmer than in winter. This has an effect on both thermals and noise, especially thermally speed-controlled fans.

The system was initially configured without the VGA card installed. The CPU fan was undervolted to 5V, and the two system fans (80mm Nexus models) ran at a full 12V. Various other configurations were tried in turn to see how the case responded to changes in airflow and system heat. Details of each configuration are listed in the table below.

QMicra Configuration Details
Configuration
CPU Temperature
GPU Temperature
System Power Draw
Noise Level
#1
- CPU Fan @ 5V
- System Fans @ 12V
Idle:
34°C
N/A
Idle:
46W
Idle:
28 dBA@1m
CPUBurn:
57°C
CPUBurn:
145W
CPUBurn:
30 dBA@1m
#2
- CPU Fan @ 5V
- System Fans @ 7V
Idle:
35°C
N/A
Idle:
46W
Idle:
24 dBA@1m
CPUBurn:
61°C
CPUBurn:
147W
CPUBurn:
28 dBA@1m
#3
- CPU Fan @ 5V
- System Fans @ 7V
- PSU ducted
Idle:
34°C
N/A
Idle:
46W
Idle:
24 dBA@1m
CPUBurn:
58°C
CPUBurn:
145W
CPUBurn:
24 dBA@1m
#4
- CPU Fan @ 5V
- System Fans @ 7V
- PSU ducted
- Passive GeForce
7600GT installed
Idle:
35°C
Idle:
48°C
Idle:
71W
Idle:
24 dBA@1m
CPUBurn:
60°C
CPUBurn:
53°C
CPUBurn:
169W
CPUBurn:
24 dBA@1m
CPUBurn +
ATI Tool:

58°C
CPUBurn +
ATI Tool:

73°C
CPUBurn +
ATI Tool:

178W
CPUBurn +
ATI Tool:

25 dBA@1m

Configuration #1

Our initial configuration did not impress us. The relatively slow-spinning Nexus fans did cool acceptably well, but the noise level was too high in comparison to other systems in the lab. To make matters worse, the fan in the power supply began to ramp up when the CPU was stressed, pushing the noise level up even more.

The character of the noise was not too bad, mostly a rippling whoosh with an underlying growl. The damping foam appeared to do its job well, as there was very little high frequency noise in evidence. The QMicra did not exhibit the ringing hum that afflicts so many aluminum enclosures. Much to our surprise, we could not hear the 120 Hz hum from the hard drive that we normally expect to hear from a hard-mounted hard drive — it blended in well with the rest of the system noise. Seek noise was audible, but surprisingly muted — far from the sharp chatter that the drive exhibits when hard mounted in a traditional drive bay.

Configuration #2

It was not difficult to improve the noise level: Turning the system fans down to 7V each dropped the noise level to 24 dBA@1m — as good as most systems get without very special attention to detail. Most of the noise reduction came from the disappearance of airflow noise; the underlying growl did not change very much. As a result, even though the system was significantly quieter (audibly as well as measurably), the quality of noise was a bit more irritating than the first configuration. Even so, it was far from terrible, and is probably good enough for most households.

Cooling at this level suffered a bit. The 61°C load temperature was higher than we like to see, but our 4800+ processor is tougher to cool than most. More unfortunate was that we still hadn't solved the problem of the power supply ramping up. As a result, the noise under load increased and the quality of noise got worse. Under load, this configuration sounded worse than any other that we tested because the bulk of the noise was the drone of the power supply fan, with little turbulence noise to smooth things out.

Configuration #3

The next step was to build a duct for the power supply to prevent it from ramping up to cope with system heat. This was easily achieved by lining the sides of the upper tray with thin closed cell foam sheets and opening the spare optical bay as an intake. The construction took about half an hour.


The quick makeshift duct to provide a dedicated fresh air intake vent for the power supply.


Front panel view of PSU intake vent / duct.

The change was dramatic: The power supply ceased to be a significant source of noise, even under load. The system now remained at a steady noise level regardless of load, at least in the moderate ambient temperature of the lab. The noise character was much the same as the idle in Configuration 2. The open drive bay did let out a bit of fan noise that was sharper than before, but the change was minor and much preferable to the increase in noise under load. (A bit of open cell foam at the entrance of the duct might help, at the expense of some intake airflow restriction.)

Surprisingly, isolating the power supply helped the CPU temperature significantly, as it dropped back below 60°C. It seems likely that the Neo HE may have been struggling for system airflow with the system fans, reducing the effectiveness of both. With the power supply isolated from the rest of the system, air could flow straight from front to back without being pulled upwards.

Configuration #4

One final configuration was tried to see how the system handled a graphics card. The test card, a passively cooled GeForce 7600GT, is not as power hungry as our recently deceased 6800GT reference card, but it also does not have a fan, and relies entirely on system airflow to remove heat.

The result of the test was much as you'd expect: CPU temperature increased slightly, but noise barely changed. The power supply did ramp up a tiny bit with both the CPU and GPU under load, but the change was barely noticeable; we had to take a measurement before we could confirm that we had heard a change.

The VGA card itself did not show any signs of overheating. The onboard sensor reported 73°C when fully loaded, which is well within the bounds of safety.



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