Lian Li PC-101: Aluminum *Can* be Quiet!

Cases|Damping
Viewing page 7 of 7 pages. Previous 1 2 3 4 5 6 7

TEST RESULTS

Ambient conditions were 24°C and 17 dBA.

The system was initially configured without the VGA card installed so that the system could be as quiet as possible. The CPU, exhaust and front intake fans were all undervolted to 5V, and the rear intake was left off entirely, since the fan on the CPU heatsink looked like it might be enough. Then, various combinations of hardware and fan configurations were tested to see how the case responded to the various changes.

Various Lian Li PC-101 Configuration Results
Configuration
CPU
GPU
HDD
System Power
Noise (SPL)
#1
Rear Intake
Off
59°C
N/A
39°C
139W
24 dBA@1m
Rear Exhaust
5V
Front Intake
5V
CPU Fan
5V
VGA Fan
N/A
#2
Rear Intake
5V
54°C
N/A
39°C
137W
26 dBA@1m
Rear Exhaust
5V
Front Intake
5V
CPU Fan
5V
VGA Fan
N/A
#3
Rear Intake
Off
CPUBurn Only:
64°C

CPUBurn +
ATI Tool:

61°C
CPUBurn Only:
61°C

CPUBurn +
ATI Tool:

76°C
CPUBurn Only: 39°C

CPUBurn +
ATI Tool:

36°C
CPUBurn Only:
195W

CPUBurn +
ATI Tool:

219W
CPUBurn Only:
24 dBA@1m

CPUBurn +
ATI Tool:

30 dBA@1m
Rear Exhaust
5V
Front Intake
5V
CPU Fan
5V
VGA Fan
5V
#4
Rear Intake
5V
CPUBurn Only:
56°C

CPUBurn +
ATI Tool:

54°C
CPUBurn Only:
60°C

CPUBurn +
ATI Tool:

72°C
CPUBurn Only: 39°C

CPUBurn +
ATI Tool:

38°C
CPUBurn Only:
190W

CPUBurn +
ATI Tool:

213W
CPUBurn Only:
29 dBA@1m

CPUBurn +
ATI Tool:

29 dBA@1m
Rear Exhaust
5V
Front Intake
5V
CPU Fan
5V
VGA Fan
5V
#5
Rear Intake
Off
N/A
N/A
39°C
Cool'n'Quiet:
43W
24 dBA@1m
Rear Exhaust
5V
Front Intake
Off
CPU Fan
5V
VGA Fan
N/A

Configuration #1

With only the Zalman 9500 at 5V to cool it, the CPU was just barely within its thermal limits. The system showed no sign of instability, but difficulties in obtaining a stable measurement for the maximum CPU told us that it was just on the edge of thermal runaway. Several times we recorded what we thought was a stable temperature, only to look again a short time later to see that the temperature had increased by a couple of degrees. The total system power also increased as the processor heated up.

The system was quieter than we had expected. Despite four fans running, the noise was kept to an acceptable growl with very little of the characteristic aluminum ringing. Much of the noise came from the hard drive in the form of a deep hum at 120 Hz. The fans themselves were quite smooth and could not be identified individually.

Configuration #2

Although the system never crashed, the CPU was clearly struggling for air in Configuration #1, so we decided to turn on the intake fan to see if we could do a better job of cooling the processor. It made a difference; the load temperature was reduced by 5°C to 54°C — an acceptable, if not optimal, level.

The additional fan had an adverse effect on system noise. The perceived increase was louder than the 2 dBA@1m increase that we measured, mainly because we could now hear the dreaded aluminum hum quite clearly. The additional noise was a medium-frequency pure tone that was much more difficult to tune out than the low growl from Configuration #1.

Configuration #3

For the third configuration, we added a graphics card of moderate power: Our old standby, the AOpen Aeolus PCX6800GT-DVD256, this time modified with Zalman a VF-900 VGA cooler at 5V. We also disabled the intake fan again, in hopes that the processor's position would prevent it from being affected by the additional 50W of heat. This is directly comparable to Configuration #2 in our review of the Zalman HD160.

Once again, the processor toed the edge of its thermal tolerances, reaching a toasty 61°C without crashing. That's significantly higher than the HD160 achieved in the same test, but it is difficult to say how different it actually is because the CPU temperature sensor was so sensitive. For the record, the ambient temperature was also 2°C lower when the HD160 was tested.

Another sign of thermal stress was the instability of the power. At full load, the peak power fluttered up and down by as much as 20W, making it impossible to take an accurate measurement. This occurred only when CPUBurn was running alone; when ATI Tool was thrown into the mix, the power variances stopped, even though the total system power was higher. The cause of the fluttering was unclear; perhaps the VRM modules that supply power to the CPU were overheating. We are not confident that the system could have sustained the heavy test load indefinitely. Eventually, we ended up doing the test a second time, recording the peak power early on before it had a chance to start fluttering.

GPU cooling was stellar, thanks mostly to the excellent VF-900 VGA cooler. The peak temperature of 76°C was well below the maximum allowable temperature for the card. However, it was also almost ten degrees higher than any temperature was saw when we reviewed the cooler — no doubt because it had to deal with the exhaust heat from the CPU.

With only CPUBurn running, the system sounded more or less the same as Configuration #1: A low growl that was quite inoffensive. The VF-900 was not a significant factor in system noise. However, once ATI Tool had been running for a short time, the fan in the power supply (a Seasonic S12-330) quickly sped up, becoming the main source of noise in the system and bringing the measured noise level up to 30 dBA@1m in the process.

Configuration #4

The questionable cooling in Configuration #3 meant that we had to turn on the intake fan again. Once again, this brought the CPU temperature down to an acceptable level, but the noise had the same pure tone as was heard in Configuration #2.

The most interesting result of turning on the fan was how it affected system power. Power consumption under load dropped by about 5W, whether or not ATI Tool was running. Even better, there was no sign of the fluttering power consumption that was seen in the earlier test. This lends credence to the theory that the VRMs were overheating, since the intake fan provides better cooling to the VRMs than the heatsink does alone.

Configuration #5

The last configuration that we tried was simply to turn off the front intake fan. Throughout the testing, the hard drive temperature had been disappointingly high for a drive with direct airflow, so we were a little apprehensive about removing the fan, but we decided to do it anyway. Surprise! Turning off the front fan had no effect on the temperature of the drive. The noise measurement did not change either, and, although the noise character lost a little bit of its fullness, the subjective difference was not large.

This suggests that, at 5V, the front fan did not generate enough pressure to draw air through the numerous restrictions in front of it. In effect, it was generating extra noise without helping cooling. This is disappointing, since it means that a noisier fan is needed to push air through the drive chamber. While our single drive was fine without airflow, a multiple drive setup would almost certainly require it.

On the topic of drives, the hard-mounted drive was one of the worst offenders from an acoustic point of view. Not only did the drive produce a significant amount of noise from the vibration is passed to the chassis, but the seeks were sharp and sounded like they were amplified by the case. Our SPL data bears this out; we measured the P120 drive at 23~24 dBA@1m in free air when we reviewed it. That should have meant that that seeks would be barely audible in the PC-101, but this was not the case. Instead, we measured the system noise at 30 dBA@1m when the drive was in use. The MP3 recording below demonstrates how intrusive the seek noise could be.

MP3 RECORDINGS

MP3: Lian Li PC-101, Config 1 (No Intake Fan): 24 dBA@1m: One Meter, One Foot

MP3: Lian Li PC-101, Config 2 (Intake Fan @ 5V): 26 dBA@1m: One Meter, One Foot

MP3: Lian Li PC-101, Config 3 (No Intake Fan, Heavy VGA Load): 30 dBA@1m: One Meter, One Foot

MP3: Lian Li PC-101, Config 5 (No Intake Fan, No HDD Fan): 24 dBA@1m: One Meter, One Foot

MP3: Lian Li PC-101, Config 1 (HDD Seek Noise): 30 dBA@1m: One Meter, One Foot

HOW TO LISTEN & COMPARE

These recordings were made with a high resolution, studio quality, digital recording system and are intended to represent a quick snapshot of what we heard during the review. Two recordings of each noise level were made, one from a distance of one meter, and another from one foot away.

The one meter recording is intended to give you an idea of how the subject of this review sound in actual use — one meter is a reasonable typical distance between a computer or computer component and your ear. The recording contains stretches of ambient noise that you can use to judge the relative loudness of the subject. For best results, set your volume control so that the ambient noise is just barely audible. Be aware that very quiet subjects may not be audible — if we couldn't hear it from one meter, chances are we couldn't record it either!

The one foot recording is designed to bring out the fine details of the noise. Use this recording with caution! Although more detailed, it may not represent how the subject sounds in actual use. It is best to listen to this recording after you have listened to the one meter recording.

More details about how we make these recordings can be found in our short article: Audio Recording Methods Revised.

CONCLUSIONS

The Lian Li PC-101 is a decent starting place for a quiet computer. It may well be the quietest aluminum case we've encountered thus far. Despite all our reservations, we were impressed at how little effort it took to build a pretty quiet system in it.

That's not to say it's not without its flaws. The rear intake fan would benefit a lot from some form of soft-mounting. Given that both of the other two fans are soft-mounted, it's puzzling why Lian Li didn't just do this themselves. As we saw, that fan is necessary to get the most out of the case, even with a CPU fan that is pulling in the right direction.

On the other hand, the processor we chose is a fairly hot one; it would have been be much easier to keep things cool if we had not chosen one of AMD's hottest processors. It would have been better for the system as a whole, since the VGA card(s) are in the path of the CPU heat exhaust.

The restrictions around the front intake were terrrible. This was the reason that slowing the fan had no effect on the temperature of HDD. Removing the filter — which is the only one in the system and therefore somewhat superfluous — would be a good first step to improving airflow in the lower chamber.

The hard-mounted drive cages are also less than ideal, though it is difficult to fault Lian Li when such mounting is the norm. The drive cages are easily removable, allowing a customized suspension of foam bed to be used.

In truth, these flaws are easily addressed, and are common to a great many other cases. However, Lian Li's high pricing may work against it. For US$200 this case should be closer to perfection, not just workable. In a $100 case, a few acoustic drawbacks are acceptable; after all, silencing is difficult to achieve without careful optimizations and lots of experience.

The best part of the PC-101 are the details. Little things like thumbscrews for everything, a clever drive mounting system, stealthed drive bays, and a spring-loaded door latch. The thick aluminum panels and a sexy appearance don't hurt either. Bottom line is, if you're looking for a case with noise as your first requirement, one of Antec's steel cases is a better place to start. On the other hand, if you want to know whether it's possible to build a quiet system in a PC-101, the answer is a positive yes. For all our complaining, we were still able to build a quiet system in the PC-101 without much effort. This is the first aluminum case we've ever been able to say that about.

Many thanks to Hampton-Technologies Inc for supplying the Lian Li PC-101 sample.

* * *

Articles of Related Interest

SilverStone Temjin TJ-06
SilverStone Temjin TJ-07
Zalman HD160 Home Theater PC Enclosure
A Reader's Report: Lian-Li PC-V2000 Tower Case
Antec P180: The Whole Nine Yards
Cases: Basics and Recommendations

* * *

Discuss this article in the SPCR Forums.



Previous 1 2 3 4 5 6 7

Cases|Damping - Article Index
Help support this site, buy the Lian Li PC-101B (Black) from one of our affiliate retailers!