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ON THE TEST BENCH
I compared the Samurai to my sort-of-reference Zalman
7000AlCu heatsink, as well as the stock Intel P4 heatsink. I used the
same processor that I've been using in all my heatsink tests, a Pentium
4, 2.4C. Yes, 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
new Samurai against all the other high performance P4 heatsinks that I've
tested during the past year.
I also tested the Samurai with the
SPCR Reference 80mm Panaflo L1A. This will let us directly compare the cooling
ability of this heatsink against other heatsinks that we have tested with the Reference fan, as per the basic SPCR heatsink testing philosophy of keeping everything the same (including the fan) and changing on the heatsink. The Samurai fan and the Panaflo L1A were both tested
blowing down on the HS as well as blowing up.
Ye Olde Test Setup
Key Components in P4 HS Test platform:
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 256MB DDRAM
Seagate 80GB Barracuda IV hard drive
Seasonic SuperSilencer 400W (rev A1) PSU
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 on the test system 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 retested 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 71-72°F (22°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.
RESULTS
The included Samurai fan controller is adjustable from a low of 1500 rpm
to a high of 3350 rpm. I tested it at both extremes as well as at the middle
of its range at 2475 rpm.
|
Full
Speed Fan Results
|
| Heatsink |
airflow direction
|
idle
|
load
|
°C
rise
|
°C/W
MP
|
°C/W
TDP
|
| Samurai
- stock fan |
up
|
26°C
|
40°C
|
18
|
0.26
|
0.27
|
|
down
|
27°C
|
42°C
|
20
|
0.27
|
0.30
|
| Samurai - Panaflo |
up
|
27°C
|
43°C
|
21
|
0.28
|
0.32
|
|
down
|
26°C
|
47°C
|
25
|
0.33
|
0.38
|
| Zalman
7000 |
down
|
24°C
|
40°C
|
18
|
0.26
|
0.27
|
| Stock Intel
HSF |
down
|
25°C
|
46°C
|
24
|
0.34
|
0.36
|
°C rise refers to the rise in
temperature over the ambient at load.
At the maximum fan speed the stock Samurai cooled quite well but
was also pretty noisy. It sounded a lot like the stock Intel HSF at full
speed: A lot of air turbulence noise and a very audible whine. There's no way this
could be used in a quiet system, but it sure
did cool well.
At full speed the Intel fan sounded as bad as the Samurai
fan but it didn't cool as well. The Zalman at 12V was certainly audible,
but not nearly as objectionable as the two other fans. At full fan speed, the Zalman cools as well
as the Samurai but its noise is lower
in level and pitch, but still not acceptably quiet by SPCR standards.
Next I swapped out the Samurai fan for the 80mm Panaflo L1A, running
at 12V. It didn't cool quite as good as the stock fan, but it was also noticeably
quieter. It had less air turbulence noise and the electrical/mechanical noise
was less objectionable as well.
After running the tests with the Samurai fans in their default "blow up"
position I flipped them over and reran the tests with them blowing down
onto the heatsink in the more normal style. Both the Samurai and the Panaflo
fans performed a few degrees worse in this orientation, showing that the
Samurais' design does work best with the fan blowing up.
(For °C/W - TDP calculations, Intel's
TDP of 66W was used. For °C/W - MP calculations, CPUHeat
& CPUMSR Projects' estimate of 75W was used)
|
Mid-speed Fan
Results
|
| Heatsink |
airflow direction
|
idle
|
load
|
°C
rise
|
°C/W
MP
|
°C/W
TDP
|
| Samurai
- stock fan |
up
|
26°C
|
44°C
|
22
|
0.29
|
0.33
|
|
down
|
28°C
|
47°C
|
25
|
0.33
|
0.38
|
| Samurai - Panaflo |
up
|
29°C
|
58°C
|
36
|
0.48
|
0.54
|
|
down
|
27°C
|
57°C
|
35
|
0.47
|
0.53
|
| Zalman
7000 |
down
|
24°C
|
41°C
|
19
|
0.27
|
0.29
|
| Stock Intel
HSF |
down
|
28°C
|
55°C
|
33
|
0.47
|
0.50
|
Next up were the mid-speed fan tests.
I set the stock fan speed to 2475
rpm, the middle of the rpm range. The Panaflo, Zalman and Intel fans were tested at 7 volts. At
this setting the Samurai fan was much quieter than at full speed.
The whine was still fairly noticeable but was at a lower level. The air
noise was also quieter but was still easy to hear from one meter away.
A slight amount of clicking started to become audible as the fan noise
and electro/mechanical noise started to recede into the background. I
was impressed by it's cooling to noise ratio at this middle speed range.
The 7 volt Samurai
fan sounds a lot like an 80mm Panaflo L1A at 12 volts. This level
of noise would be acceptable in a system running around 30-35dBA/1m.
The Zalman still worked very well at 7V and its noise was pretty unobtrusive, consisting of a slight bit of air noise and a quiet clicking. The Intel
HSF was already starting to breath pretty hard at this voltage and still
had a bit of whine and air noise.
The Samurai did not coo very well with the Panaflo L1A at 7 volts, blowing up or down. It's just not
moving enough air at 7 volts to cool effectively. It's the quietest of
all four fans at this mid-speed setting.
Repeating the tests with the Samurai
fan in the blow down mode gave results almost exactly like the 12 volt tests,
with the blow up orientation a few degrees cooler.
|
Low
Speed Fan Results
|
| Heatsink |
airflow direction
|
idle
|
load
|
°C
rise
|
°C/W
MP
|
°C/W
TDP
|
| Samurai
- stock fan |
up
|
28°C
|
51°C
|
29
|
0.39
|
0.44
|
|
down
|
28°C
|
53°C
|
31
|
0.41
|
0.47
|
| Samurai - Panaflo |
up
|
28°C
|
74°C
|
52
|
0.69
|
0.79
|
|
down
|
28°C
|
72°C
|
50
|
0.67
|
0.76
|
| Zalman
7000 |
down
|
26°C
|
45°C
|
23
|
0.33
|
0.35
|
| Stock Intel
HSF |
down
|
28°C
|
64°C
|
42
|
0.60
|
0.63
|
At 5V the stock Samurai fan still cooled decently
and was very quiet. There was just the slightest bit of air noise and
a very slight amount of clicking that sounded more like very quiet static
than actual clicking. I was impressed with its cooling-to-noise
ratio at this minimum speed. Of course the good 'ol Zalman was still working
just fine down at 5V. Its cooling performance was still very good and
it's noise level was very quiet. I could barely hear any wind noise and
just the slightest bit of very quiet clicking from about .5-1 meter away.
The Intel HSF is basically useless at 5V. Load temps were pretty high
and its whine and hum were louder than any of the other fans in
this test.
Switching from the Samurai fan to the Panaflo at 5 volts
was a basically worthless endeavor. The Panaflo at 5 volts gave
load temps in the low to mid 70°C range, which is unacceptable.
It is the quietest of all the tested fans at their lowest settings,
but much quieter than the stock Samurai fan. The
Samurai fan at min speed is nearly as quiet as the Panaflo but cools over 20°C
better.
Scythe claims that their Samurai cooler will cool "all Pentium 4 processors"
but I only tested it with the (relatively) moderate output of the 2.4C
processor. We can however, use the "°C/W" numbers to extrapolate
the theoretical performance of the Samurai to any other P4 processor, including
the 100+ watt P4 3.4GHz Prescott. According to Intel's "TDP"
specs, the 3.4 Prescott puts out 103W. The higher "MP"
power rating for the 3.4Ghz Prescott is 115 watts so we'll use those numbers
to calculate the estimated maximum CPU temperature for a 3.4E running 2xCPUBurn:
Extrapolated Samurai temps for a 103W, 3.4GHz Prescott
using the "TDP" power rating
| Fan RPM |
C/W
|
°C rise
|
load
|
| 3350 (max) |
0.27
|
28
|
50°C
|
| 2475 (mid) |
0.33
|
34
|
56°C
|
| 1500 (min) |
0.44
|
45
|
67°C
|
Extrapolated Samurai temps for a 115W, 3.4GHz Prescott
using the "MP" power rating
| Fan RPM |
C/W
|
°C rise
|
load
|
| 3350 (max) |
0.26
|
30
|
52°C
|
| 2475 (mid) |
0.29
|
33
|
55°C
|
| 1500 (min) |
0.39
|
45
|
67°C
|
Depending on how much faith you have in these calculations,
it does look like the Samurai is capable of cooling the hottest running
current P4 CPU, at least down to its mid-speed fan setting. Whether this noise level is acceptable depends on your
choice of system hardware, ambient noise level and personal noise tolerance.
I mentioned earlier was that there's no good way to determine
whether the mounting tension is correct. I initially tightened
them down as much as I felt comfortable. I found that my original setting was fine;
tightening it any more made no difference in load temps. I was
able to loosen it up enough to give higher temps, but it was seemed fairly easy to tell that this was not
enough pressure. Hopefully the average builder will be able to determine
the correct amount of pressure, since the mounting instructions are rather
vague.
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