Zalman's new 9700 bigboy heatsink/fan

Cooling
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TESTING

Testing was done according to our unique heatsink testing methodology, and some of the fan's characteristics were measured using our standard fan testing methodology. A summary of the components, tools, and procedures follows below.

Key Components in Heatsink Test Platform:

Test Tools

  • Seasonic Power Angel for measuring AC power at the wall to ensure that the heat output remains consistent.
  • Custom-built, four-channel variable DC power supply, used to control the fan speed during the test.
  • Bruel & Kjaer (B&K) model 2203 Sound Level Meter. Used to accurately measure SPL (sound pressure level) down to 20 dBA and below.
  • Various other tools for testing fans, as documented in our standard fan testing methodology.

Software Tools

  • SpeedFan 4.31, used to monitor the on-chip thermal sensor. This sensor is not calibrated, so results are not universally applicable, however.
  • CPUBurn P6, used to stress the CPU heavily, generating more heat that most realistic loads. Two instances are used to ensure that both cores are stressed.
  • Throttlewatch 2.01, used to monitor the throttling feature of the CPU to determine when overheating occurs.

Sound pressure level (SPL) measurements were made with the fan powered from the lab variable DC power supply with no other noise sources in the room. The ambient conditions during testing were 18 dBA and 22°C.

Load testing was accomplished using CPUBurn to stress the processor, and the graph function in SpeedFan was used to make sure that the load temperature was stable for at least ten minutes. The fan was tested at four voltages: 5V, 7V, 9V, and 12V, representing a full cross-section of the its airflow and noise performance.

MEASURED TEST RESULTS

Zalman CNPS9700
Voltage
RPM
SPL
Temp
°C Rise
°C/W
12V
2810
40
35°C
13°C
0.17
9V
2250
34
36°C
14°C
0.18
7V
1780
30
39°C
17°C
0.22
5V
1250
23
41°C
19°C
0.24
3.7V*
860
20
46°C
24°C
0.31
SPL: Sound Pressure Level measured in dBA@1m
Load Temp:
CPUBurn for ~20 mins.
°C Rise: Temperature rise above ambient (22°C) at load.
°C/W: Temperature rise over ambient per Watt of CPU heat, based on the amount of heat dissipated by the CPU (measured power of 78W).
Noise: SPL measured in dBA@1m distance with high accuracy B & K SLM
3.7V*: This was the slowest we could run the fan while still achieving reliable startup. Note that the exact minimum reliable start voltage will vary a bit with fan sample and temperature.

@ 12V: Most readers will know that 40dBA is simply too high to be considered quiet. Unfortunately, the noise characteristics of the fan don't help. The fan exhibited noises that we seek to avoid — growling, buzzing. On a positive note, the cooling of the heatsink was excellent.

@ 9V: This small decrease in the fan voltage did wonders for the overall noise level of the fan. Still not quiet enough to be considered "SPCR worthy", but substantially less irritating than before. Temperatures barely rose, meaning we still had quite a ways to go before running into troubles.

@ 7V: The fan now became more reasonable in its overall sound. However, it still had unpleasant undertones that couldn't be ignored. The performance of the heatsink didn't seem fazed much by the reduction in fan speed, staying at just 17°C rise above ambient.

@ 5V: Another 2V drop in the fan voltage brought a welcome 7dBA drop in noise levels. The undertones of the fan remained, but were much less noticeable now than before. What is most surprising about this setup is that the overall performance of the heatsink dropped only 6°C from the full 12V fan speed. It seems like there was still headroom left at lower fan speeds, so we decided to see how low we could go.

@ 3.7V: This was the slowest we could run the fan while still achieving reliable startup. The noise levels dropped again, as expected, but the overall character of the noise remained the same. Cooling performance still stayed acceptable by all measures. This heatsink can definitely keep things cool. (Note that the exact minimum reliable start voltage will vary a bit with fan sample and temperature.)

COMPARABLES

The 9700 falls into the most ambitious category of heatsinks in size, design and price. Naturally, we want to compare it to the other recent top performers.

Reference 120mm fan w/ Scythe Ninja + Thermalright Ultra-120
Fan Voltage
RPM
SPL
dBA@1m
Scythe Ninja
Ultra-120
°C Rise
°C/W
°C Rise
°C/W
12V
1080
22
14
0.18
15
0.19
9V
850
19
16
0.18
17
0.19
7V
680
<19
17
0.20
21
0.21
5V
490
<18
21
0.21
26
0.27

We run into an immediate problem. Two of the top performers we've reviewed, the Scythe Ninja and the Thermalright Ultra-120, both come fanless, for use with your choice of 120mm fan. Our choice is our reference super-quiet Nexus 120. This fan's maximum speed at 12V of 1080 rpm is slower than the 9700 fan's minimum speed of 1250 rpm that is selectable by the user on the Fan Mate 2.

Let's assume for the sake of comparison that at the same rpm, the Nexus 120 blows 10% more air than the 110mm fan on the Zalman 9700. Then at least we can try to make some kind of comparison table. As you know from the SPCR Search Engine listing at the bottom of the page, the 9700 runs over $65. With Nexus 120. either the Scythe Ninja or the Thermalright Ultra 120 runs about $60.

Zalman 9700 Vs Nexus 120mm fan on Scythe Ninja + Thermalright Ultra-120
Zalman 9700
Nexus 120 fan
Ninja
Ultra-120
RPM
SPL
°C Rise
RPM
SPL
°C Rise
°C Rise
1250
23
19
1080
22
14
15
860
20
24
850
19
16
17
-
-
-
680
<19
17
21
-
-
-
490
<18
21
26

There's not much contest when the very first comparison shows a 4~5°C advantage for the established leaders. This is at the lowest practical noise level that the Zalman is capable of: Minimum setting or 5V on the Fan Mate for an SPL of 23 dBA@1m. Only when we run the Zalman 9700 fan at a voltage level well below the lowest available on the Fan Mate — 3.7V is not something most users will be able to achieve — do we get to 20 dBA@1m. When it comes to performance in the context of low noise, the 9700 doesn't fare well against the competition of the big towers and the reference quiet 120mm fan. Add the higher price tag to the mix, and the match is over.

What about against the smaller 9500?

Zalman 9700 Vs Zalman 9500
9700
9500
Voltage
RPM
SPL
°C Rise
Voltage
RPM
SPL
°C Rise
12V
2810
40
13
12V
2620
37
13
9V
2250
34
14
9V
2130
32
16
7V
1780
30
17
7V
1670
27
16
5V
1250
23
19
5V
1290
22
19

The 9700 may have a cooling edge, but it doesn't really show up here. The bigger fan and larger cooling surface area should result in some cooling advantage with a CPU hotter than our testbed's Intel D950 (which has an official TDP of 130W) — but at this point, such a hot processor is no longer so common, and most run much cooler.

The larger fan hasn't helped reduce noise levels at all, in fact, it generally measures louder. The subjective sound of 9500 fan is more whiny, while the 9700 has more of a grinding, lower pitch sound. Neither are favorable, and the fans on either model can be modded to replace the stock fan like we did with the 9500. But there's increased cost and no cooling performance gain.

NOISE RECORDINGS IN MP3 FORMAT

Zalman CNPS9700: 5V-7V-9V-12V, with 5s ambient between levels: One Meter, One Foot (30cm)

Comparatives:

Scythe Infinity: 5V-7V-9V-12V, 5s Ambient between levels: One Meter, One Foot (30cm)

Nexus 120mm fan: 5V-7V-9V-12V, 5s Ambient between levels: One Meter, One Foot (30cm)

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 (30cm) 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 article: Audio Recording Methods Revised.

CONCLUSIONS

Zalman is usually on the forefront of innovative cooling designs. The earlier 9500 heatsink fan was a very nice design. The 9700 is more of the same, but without any compelling advantages that we could measure or hear. The bigger fan and larger cooling surface area may result in some cooling advantage with a super hot processor, but currently such hot processors are no longer common, and many more run much cooler.

The 9700 does have very good cooling performance, but the stock fan doesn't do it justice. It's a lousy fan, about the worst integrated one we've seen from Zalman. It's the nadir of the trend that began with the first fans Zalman offered some half dozen years ago. It's a mystery. There seems some kind of internal disconnect within the firm. How does a company born on the concept of quiet cooling, a company that even uses the slogan Computer Noise Prevention System as part of its model numbering (CNPS), continue to put the most mediocre, bad-sounding fans on its heatsinks? Don't they listen?!

Having said that, is it possible that the acoustic performance of this fan is due to some damage done in transit? Yes, it's possible, anything is possible, but it seems unlikely. We'd need to hear and examine at least a couple other samples to be sure. Zalman may wish never to speak to us again, though.

There are still many good things to say about the 9700, however: As already mentioned, the basic design is clever and aesthetically pleasing. More importantly, the positive, no-guessing mounting system is excellent, just as it was with the 9500. With a quick read of the instructions and a screwdriver, the heatsink is installed within a matter of minutes, no cursing required. This type of positive, secure HS installation system is definitely something we'd like to see more of. (Of course, if you have to pull your entire system apart to get the motherboard out of the case in order to mount the heatsink, you won't be quite as delighted.)

If silence is what you seek, the CNPS9700 isn't for you. On the other hand, if you aren't bothered by the noise, the CNPS9700 will do a fine job of keeping your system running cool.

Pros

* Good cooling performance
* Excellent mounting system
* Included fan controller
* Good low-airflow performance
Cons

* Noisy at any speed
* On the heavy side
* Expensive

Much thanks to Zalman for the CNPS9700 LED sample.

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Articles of Related Interest

Recommended Heatsinks
SPCR's unique heatsink testing methodology
SPCR's standard fan testing methodology
Scythe Infinity
Thermalright Ultra-120
Zalman CNPS9500

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