Thermaltake CL-P0025 Silent Tower CPU heatsink/fan

Cooling
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ON THE TEST BENCH

For this test I compared the 92mm Silent Tower to my sort-of-reference 92mm fan equipped Zalman 7000AlCu heatsink. I used the same processor that I've been using in all my heatsink tests, a Pentium 4, 2.4C. It may not put out as much heat as a new Prescott, but using this processor will allow me to directly compare the performance of the Silent Tower against all the other P4 heatsinks that I've tested during the past year.

I was not able to test the Silent Tower in full accordance with the standard SPCR testing method, which calls for the HS to be used with SPCR Reference 80mm Panaflo L1A. Nothing but 92mm fans will fit on the intake side. I decided to test several different types of quiet 92mm fans on the Silent Tower, to get a good feel for its performance. I used the included Thermaltake augmented fan, as well as a 92mm Panaflo L1A and a 92mm Nexus. I also set up the heatsink using two Nexus 92 fans in a "push-pull" configuration, which Thermaltake claims gives better cooling.


Ye Olde Test Setup.

HS TEST PLATFORM & PROCEDURE

The P4 HS test platform is an open system not enclosed in a case.

Intel P4-2.4C Northwood core - Maximum power is 66.2W.
Intel 875PBZ motherboard - Intel 875P Chipset; on-die CPU thermal diode monitoring
ATI Radeon 7500 passively cooled video card (AGP)
Mushkin PC3200 Level II - 2 x 512MB DDRAM
Seagate 80GB Barracuda IV hard drive
Seasonic SuperSilencer 300W (rev A1) PSU modded with 5V Panaflo M1A
Arctic Silver Ceramique Thermal Compound
Two-level metal platform with rubber damping feet. Motherboard on top; other components below.
CPUBurn processor stress software
Motherboard Monitor 5.3.4.0 software to track CPU temperature and fan speed

Each heatsink was cleaned and installed as per the manufacturer's and Arctic Silver's instructions. Prime95 was then run for 8 hours to verify system stability and cure the Ceramique. The system was then shut down and not restarted until the next morning when the actual testing was done. The system was allowed to cool between tests for 30 minutes. Each test was run for 30 minutes even though all temperatures generally stabilized within 15 to 20 minutes.

Each heatsink was tested three times on consecutive mornings to check to the consistency of the results. All results were within 1-2°C of each other and the average readings are included in the charts.

Ambient temperature was measured at 71°F (21°C) over the entire series of tests. No tests were run unless the ambient temperature was at that reference level.

* All temperatures in degrees Celsius.
* Diode: Reading from P4-2.4C CPU diode via Motherboard Monitor.
* Temp Rise refers to the difference between ambient temperature and the diode reading. .
* °C/W refers to the °C of temperature rise per watt of heat dissipated by the CPU.

COOLING AND ACOUSTICS FINDINGS

I tested the heatsink with each of the fans at 12V, 7V and 5V, mounted in the default Thermaltake "blowing" orientation. I also did one series of tests using two of the Nexus fans mounted in a "push-pull" configuration.

The first column on the left contain links to sound recordings in MP3 format. The second column shows the sound pressure level of each fan, measured at a distance of one meter in a room of ~16 dBA ambient noise. This information comes from the SPCR Acoustics Lab, with the data and recordings provided by Mike Chin and Sean Boyd. The stock Silent Tower fan was not measured or recorded because it was not present in the lab.

SPCR MP3s: HOW TO LISTEN & COMPARE

The recordings above were made with a high resolution studio quality digital recording system. The microphone is 3" from the edge of the fan frame at a 45° angle, facing the intake side of the fan to avoid direct wind noise. The ambient noise during all recordings is 20 dBA or lower.

A quick and simple way to use these recordings for valid listening comparisons is to play the quietest recording on only one speaker (or a pair of headphones) and set the volume so it is just barely audible a meter away. You must turn off any special sound effects, and set equalizer / tone controls to neutral or flat. Don't touch the volume setting afterwards, and use the same one speaker when you listen to any of the other files. The end result will be reasonably close to the actual recorded sound levels.

Here is a recording of a very quiet fan that is barely audible from 1 meter away even in a super quiet room.

For full details on how to calibrate your sound system to get the most valid listening comparison, please see the yellow text box entitled Listen to the Fans on page 3 of the article SPCR's Test / Sound Lab: A Short Tour.

It may be enlightening to download the MP3 files and listen for yourself. You don't have to take my word about what they sound like.

12V Fan Results
Heatsink / Fan - MP3 recording
dBA@1m
idle
load
°C rise
°C/W MP
°C/W TDP
Silent Tower w/ stock fan
???
24°C
34°C
13
0.17
0.20
Silent Tower w/ Panaflo 92L
35
24°C
34°C
13
0.17
0.20
Silent Tower w/ Nexus 92mm
20
25°C
41°C
20
0.27
0.30
Zalman 7000AlCu
34
24°C
40°C
19
0.25
0.29
°C rise refers to the rise in temperature over the ambient at load.
°C/W - TDP calculations: Intel's TDP of 66W was used.
°C/W - MP calculations: CPUHeat & CPUMSR Projects' estimate of 75W was used.

AT 12 Volts, the HS cools very well with every fan. Unfortunately, all but the 92mm Nexus are too noisy for serious consideration by SPCR readers. The stock Thermaltake is the loudest by a large margin, followed by the L1A Panaflo, then the Zalman with the Nexus coming in as the quietest by far. The Thermaltake fan is particularly obnoxious, with a loud whine, a raspy buzz, noticeable clicking and a lot of air noise. By no stretch of the imagination could this fan be considered "silent", or even quiet.

The Panaflo cools just as well as the stock fan, but had no raspiness, less whine and much less air turbulence noise. So much for the "augmented" fan design giving more airflow with less noise. The 92mm Nexus is the standout, giving excellent cooling performance at very low noise levels. The Nexus at 12V is very quiet, perhaps as loud as the Zalman 7000 fan at 6-7V.

7V Fan Results
Heatsink / Fan - MP3 recording
dBA@1m
idle
load
°C rise
°C/W MP
°C/W TDP
Silent Tower w/ stock fan
???
25°C
39°C
18
0.24
0.27
Silent Tower w/ Panaflo 92L
26
25°C
42°C
21
0.28
0.32
Silent Tower w/ Nexus 92mm
17
27°C
51°C
30
0.40
0.46
Zalman 7000AlCu
25
24°C
41°C
20
0.27
0.31

AT 7 Volts, the Thermaltake and the Panaflo cool quite well, but the Thermaltake fan is not much quieter than at 12V. It still has the clicks, whine, buzz and turbulence noise, albeit at a bit lower level. This excessive air turbulence noise seems to be a common trait on every augmented fan I've ever heard. The L1A isn't too bad at 7V, but is certainly louder than the Zalman fan even though both provide the same cooling performance. The Nexus is nearly silent at 7V, but obviously running out of steam; the cooling performance is barely acceptable.

5V Fan Results
Heatsink / Fan - MP3 recording
dBA@1m
idle
load
°C rise
°C/W MP
°C/W TDP
Silent Tower w/ stock fan
???
26°C
46°C
25
0.33
0.38
Silent Tower w/ Panaflo 92L
20
27°C
50°C
29
0.39
0.44
Silent Tower w/ Nexus 92mm
16
29°C
59°C
38
0.51
0.58
Zalman 7000AlCu
20
26°C
45°C
24
0.32
0.37

AT 5 Volts, the stock fan was finally becoming somewhat quiet but it still had a distinct whine, a low metallic hum and audible clicking, with little air noise. The Panaflo at 5V is, well, a 92mm Panaflo: Not one of Panaflo's quietest with an audible clicking and a bit of whine, but is probably sufficiently quiet for many less-than-hardcore silent PC builders. The Zalman is subjectively quieter than the Panaflo with slightly better cooling ability. The Nexus is super quiet but at the expense of any useful airflow.



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