L a r s V i l h u b e r
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tidbits from noise/temp testing

08/27/2003 02:36 PM

Noise:

I probably should get a noise meter, but the "20dbA" fan I got (Vantec Stealth 92mm double-ball bearing, 1750RPM/20dBA) seems a lot louder than than 20dBA (i.e., I shouldn't be able to hear 20dBA...) I *don't* hear the Panaflo fan in the power supply (2950RPM/32dBA).

Current fans in system:

  • CPU and fan: AMD XP 1800+ (1533 Mhz) with factory default fan, on a continuous variation fan speed regulator from Zalman. At max, runs at 3300 (loud whine), at min, around 1500 (below measurable by ear and motherboard RPM monitor).
  • Power supply: Panaflo 80mm Hydro Wave Bearing Fan High Volume (FBA-08A12H), replaces the default (single) fan in my power supply (2950RPM/32dBA)
  • Case fan: Vantec Stealth 92mm double-ball bearing, 1750RPM/20dBA. Couldn't fit a Panaflo, because they do not make 92mm fans [UPDATE: actually they do, but they are hard to find]... Actually, I can't even find a 92mm-to-80mm adapter (lots of 80mm-to-92mm)

Temperature:

ran the following test:
  • 10 min pre-quiet time, 60 sec measurements of CPU and SYS temp
  • clean kernel compile (typically around 6-7 minutes), 60 sec measurements
  • 10 min post-quiet time, 60 sec measurements

Results:

(for each, last pre-quiet PQ), highest compile (HC)) ordered by perceived noise (decreasing) 
CPU-max CASE FAN yes:
PQ: +45.4°C   +31.2°C
HC: +51.3°C   +31.3°CYes
6 minutes back to quiet

CPU-max CASE FAN no:
PQ: +48.5°C   +37.7°C
HC: +54.6°C   +37.6°CYes
10 minutes back to quiet

CPU-mininum CASE FAN yes:
PQ: +47.5°C   +30.1°C
HC: +54.1°C   +29.9°CYes
6 minutes back to quiet

CPU-min CASE FAN no:
PQ: +54.9°C   +39.1°C
HC: +62.3°C   +38.8°C
7 minutes back to quiet

It looks like the case fan successfully lowers the CPU temperature by at least 2°C (with CPU fan at minimum, by 7 degrees). But in all cases, the temperature is below recommended case/max cpu temps (http://www.casecooler.com/temandvolgui.html): case <= 42, cpu <=95.

I will probably simply get another RPM control ($7) and just adjust it upwards when the house temperature is high (summer, during 6 weeks...)

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