Scythe FCS-50 heatsink/fan

Cooling
Viewing page 4 of 5 pages. Previous 1 2 3 4 5 Next

TESTING

The core of the test system is very similar to that used in the past, but a few minor components have changed and test tools added:

  • Intel P4-2.8A The Thermal Design Power of this P4-2.8 (533 MHz bus) is 68.4 or 69.7W depending on the version. As the CPU is a demo model without normal markings, it's not clear which version it is, so we'll round the number off to ~69W. The Maximum Power, as calculated by CPUHeat & CPUMSR, is 79W.
  • Intel D845PEBT2 motherboard - Intel 845PE Chipset; on-die CPU thermal diode monitoring
  • Panaflo FBA08A12L1A 80mm DC fan
  • nVidia GF400MX VGA card (AGP)
  • OCZ DDRAM PC-3700, 512 MB
  • Seagate Barracuda IV 40G 1-platter drive (in Smart Drive from Silicon Acoustics)
  • Enermax UC-A8FATR4 multifunction monitor/fan controller w/ thermal sensors
  • Seasonic Super Tornado 300 (Rev. A1)
  • Zalman Multi-Connector (ZM-MC1) and Fanmate1 voltage controller
  • Arctic Silver Ceramique Thermal Compound
  • Two-level plywood platform with foam damping feet. Motherboard on top; most other components below. Eases heatsink changes and setup.
  • CPUBurn processor stress software
  • Intel Active Monitor and Motherboard Monitor software to show CPU temperature

The ambient temperature in the test lab was 22°C. Ambient noise in the lab was ~21 dBA. For the acoustic testing, the HSF was moved to a quieter room which measured ~16 dBA. Maximum load temperatures were recorded 30 minutes into a CPU stress test with CPUBurn.

TEST A: Stock Fan

The FCS-50 was tested at four fan settings, mid being the midway point on the control knob. The noise was measured separately with the HSF in a quieter space with no other equipment running at all. Note that by itself in free air, the fan's noise drops by 1~2 dBA at lower speeds and 3~6 dBA at high speeds.

The borderline setting was established by ear. It is the level at which the very quiet components of this test rig still mask the HSF noise. In other words, if the fan was run any faster, I would start to hear it as a distinct noise source, separate from other noises, from a couple feet away. Inside a case, it's likely to remain masked to a slightly higher speed.

STOCK FAN
Idle temp*
Max temp*
Temp rise*
°C/W
TDP
°C/W
MP
Noise**
Max
(4800 RPM)
34
39
17
0.25
0.22
50
Mid
(2330 RPM)
39
44
22
0.32
0.28
36
Borderline
(1600 RPM)
41
52
30
0.43
0.38
22
Min
(1330 RPM)
42
56
34
0.49
0.43
20
* Idle, Max and Temp rise figures all in °C.
** Noise in dBA @ 1m distance.
TDP (Thermal Design Power of CPU) = 69W
MP (Maximum Power of CPU) = 79W

1) At Maximum speed, this hypro-bearing fan is a screaming, whooshing monster. The airflow is strong enough to be felt over 8 feet away. The cooling performance is super, so perhaps it's a dream for an overclocker, but it's a nightmare for me. It's a smooth not grating sound, but it's loud. 50 dBA/1m is 4 dBA louder than cited in the specs, but the difference is essentially meaningless; either level is too loud. It is loud enough to be heard faintly from two rooms away at the top of the stairwell on the next floor. Great performance, but as Scythe implies, it is the Mr. Hyde side of the FCS-50 (2-in-1, remember?).

2) At Mid speed, the performance holds up well; it is still very good. A 22°C rise over ambient at max is nothing to scoff at. The noise is still too high for SPCR, but might be acceptable in a noisier environment than mine inside a well-damped case. The main character of the noise is turbulence noise and some whine. Basically fairly benign and smooth, but there's just too much of it.

3) The Borderline speed actually represents a speed setting technique I've used intuitively for years without ever writing about it before. Every system has components whose noise just can't seem to go below a certain level. When another fan is introduced, adjust its speed so that when you just start to hear it, you back off just a touch. At this point it is at the borderline of audibility. The new fan's noise is masked by the other components in the system and so adds no significant noise.

The borderline speed with this HSF in this system turned out to be 1600 RPM, at which speed it produces 22 dBA/1m in free air. It's very quiet, and performance is still decent. If you add 10°C to the ambient simulate the inside of a case, the P4-2.8 would be at ~62°C, which is perfectly safe. (Remember that's after a continuous half hour of the toughest CPU load we can find.) The basic sonic character of the fan is a bit of turbulence whoosh along with a bit of buzzing from the bearing, somewhat higher than I find on Panaflos. That's the only significant bearing/ motor artifact. It's not bad at all. Inside a case it could be inaudible.

4) At Minimum speed, the fan is very quiet. There is no turbulence noise, but the buzzing mentioned above seems a bit louder, and a humming noise also ensues. It's not as quiet as a Panaflo 80L at 7V. Still it's probably good enough for most users. The cooling power is now borderline. 34°C over ambient at load puts the CPU at 66°C, which is starting to get into uncomfortable territory. It's probably still perfectly usable unless your ambient and case temperatures are higher, and you routinely push the system to such high continuous loads over long periods of time.

TEST B: Panaflo 80L Fan

The FCS-50 was tested with our reference Panaflo 80mm hypro bearing, low speed fan at three voltages: 12V, 9V and 7V. The noise was measured separately with the fan on the HS in a quieter space with no other equipment running at all. Note that by itself in free air, the fan's noise does not measure or sound any different except at the 12V level. Airflow from the Panaflo is probably too low for turbulence in this HS to cause extra noise. As mentioned previously, the four screws provided are too short for the Panaflo, which is a touch deeper than the Scythe stock fan, but I scrounged up some slightly longer screws to do the job.

Reference Panaflo Fan Summary

Table 1: Panaflo FBA08A12L1A Speed, Airflow and Noise
VDC
12V
9V
7V
5V
RPM*
1880
1520
1230
760
dBA @ 1m**
24
19
16~17
???
* RPM was measured on two Panaflo samples using MBM5 along with a custom-made tachometer board provided by Fan Control, an electronics-savvy member of the SPCR Forum. This device allows accurate readings of fan speed down to much below 1000 rpm, which is usually not possible with standard on-board sensors. The readings from the two fans were averaged for the above table.
** dBA@1m noise figures were measured with the fan suspended in free air without any load. The noise could not be measured consistently at the 5V drive level because the ambient level in the acoustic lab was too high. My guess: ~15 dBA/1m, maybe lower.

FCS-50 + Panaflo Results

PANAFLO 80L
Idle temp*
Max temp*
Temp rise*
°C/W
TDP
°C/W
MP
Noise**
12V
38
45
23
0.33
0.29
25
9V
41
51
29
0.32
0.37
19
7V
45
59
37
0.54
0.47
17
* Idle, Max and Temp rise figures all in °C.
** Noise of fan on HS in free air, in dBA @ 1m distance.
TDP (Thermal Design Power of CPU) = 69W
MP (Maximum Power of CPU) = 79W

1) With the Panaflo at 12V, the FCS-50 turns in a very nice performance. It is certainly good enough for performance enthusiasts and even overclockers, and the noise level is quite modest. In many systems, the Panaflo even at 12V is not much of a noise hardship. There is a touch of whine, but overall, the sound is smooth and easy on the ear.

2) With the Panaflo at 9V, performance remains fine. It is roughly on par with the performance of the stock fan at the borderline 1600 RPM setting. The noise is substantially lower (by 3 dBA) and smoother, with less buzz or hum. This is probably quiet enough for lots of PC silencers.

3) With the Panaflo at 7V, noise drops down to about inaudible in most systems and most environments. It can be heard if you get close enough. There is a bit of hum, and maybe a touch of chuffing, but both are at very low levels. You have to work to hear them, Inside most PCs, with all the other noise makers, it would be masked most of the time. Cooling performance is probably not good enough for most users with this CPU, however. A cooler CPU would make the 7V Panaflo a more viable option with the FCS-50.

4) DUAL 7V Panaflos in Push-Pull

It just had to be tried. The results were not great, however. As you can see in the table below, two Panaflos at 7V in push-pull are not as effective as a single Panaflo at 9V, and it's even noisier. The Bottom Line: Push-pull is probably more useful where there is greater impedance and the airflow needed is higher than is usually used for silent computing.

PANAFLO 80L
Idle temp*
Max temp*
Temp rise*
°C/W
TDP
°C/W
MP
Noise**
one, 7V
45
59
37
0.54
0.47
17
two, 7V; in push-pull
43
52
30
0.43
0.38
20
one, 9V
41
51
29
0.32
0.37
19
* Idle, Max and Temp rise figures all in °C.
** Noise of fan on HS in free air, in dBA @ 1m distance.
TDP (Thermal Design Power of CPU) = 69W
MP (Maximum Power of CPU) = 79W



Previous 1 2 3 4 5 Next

Cooling - Article Index
Help support this site, buy from one of our affiliate retailers!
Search: