Zalman CNPS7700-AlCu Heatsink/Fan

Cooling
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COMPARISONS

1) Against the Zalman CNPS7000-AlCu

Rather than retrieve and extrapolate data from earlier reviews, a fresh set of tests were run with the 7000 on this new test platform. The table below shows the results.

Zalman CNPS7000-AlCu
Fan Voltage (V)
Airflow (CFM)
SPL (dBA/1m)
Load Temp (°C)
°C Rise from ambient
°C/W MP
°C/W TDP
12
23
39
41
20
0.25
0.29
9
15
33
43
22
0.28
0.32
7
11
28
45
24
0.30
0.35
5
8
22
48
27
0.34
0.39

A side by side look at the most salient data of the 7000-AlCu and the 7700-AlCu:

Fan Voltage (V)
Airflow (CFM) SPL (dBA/1m) °C Rise from ambient
7700
7000
7700
7000
7700
7000
12
32
23
38
39
18
20
9
25
15
32
33
20
22
7
18
11
28
28
22
24
5
12
8
22
22
25
27

It's surprising, but the smaller 7000 measures a tad higher with the fan at higher speeds and is essentially at the same loudness at slower speed. These findings contradict Zalman's own specs. In listening, the smaller 7000 fans always sounds a bit higher pitched because it is spinning faster, and the larger 7700 fan has a touch more growl. Which you prefer is probably a tossup and dependent on your own hearing. Practically speaking, there's not much acoustic difference.

In terms of cooling, the larger 7700 stays ahead by at least 2°C at the higher fan speeds, and increases the gap to 3°C at low fan speeds. This is a significant if not earth-shattering difference that will come in handy with hotter CPUs.

2) Against the Thermalright XP-120

We crowned the Thermalright XP-120 as the new king of coolers a few months ago. The XP-120 is the only other 120mm fan CPU cooler we know of and from a brand that's been neck-and-neck with the Zalman for top HS honors for 2~3 years, so the comparison is a natural.

Again, rather than rely on previous data -- ably collected in the XP-120 review by Ralf Hutter but on a different platform and a different CPU -- a new set of tests was conducted with the XP-120 on this platform.

There are many 120mm fans that can be used with the XP-120. In order to keep this review from ballooning into an unwieldy tome, only one fan was used: The Globe S1202512L-3M, the quietest 120mm fan employed by Ralf Hutter in his XP-120 review. This sleeve-bearing fan is thermally controlled via a thermistor at the end of a long lead that emerges from the hub. The thermistor was shorted to take the thermistor out of the circuit so that the fan speed could be controlled directly.

The Globe fan was placed atop the XP-120, blowing down only. The voltage to the fan was carefully adjusted to give the same CFM values measured at 12, 9, 7 and 5V with the Zalman 7700. In this way we're comparing the two heatsinks with very similar amounts of airflow.

Thermalright XP-120 w/ Globe S1202512L-3M fan
Fan Voltage (V)
Airflow (CFM)*
SPL (dBA/1m)
Load Temp (°C)
°C Rise from ambient
°C/W MP
°C/W TDP
8
32
27
38
17
0.22
0.25
6.8
25
23
40
19
0.24
0.28
5.4
18
20
42
21
0.27
0.30
4.5
12
18
45
24
0.30
0.35
12*
47
39
36
15
0.19
0.22

The airflow / noise ratio of the 7700 fan and the Globe fan are quite different. There is no way that the Zalman 7700 fan can match the maximum airflow of the Globe fan at 12V. (*The 12V results in the table above are listed at the bottom and in gray to show that there is no comparable data for the Zalman 7700-AlCu. Note that this noise level is about the same as with the 7700 at 12V, but the temperature is 3°C lower.)

Below, then, is a side-by-side comparison of the core data for the Zalman 7700AlCu and the Thermalright XP-120 with Globe 120mm low speed fan.

Airflow (CFM)* Fan Voltage (V) SPL (dBA/1m) °C Rise from ambient
7700
XP-120 / Globe
7700
XP-120 / Globe
7700
XP-120 / Globe
32
12
8
38
27
18
17
25
9
6.8
32
23
20
19
18
7
5.4
28
20
22
21
12
5
4.5
22
18
25
24

Airflow is the reference for the table above; the voltage for each fan was set so that the airflow would be the same for both HSF. The Globe fan requires less voltage to provide the same airflow level. At the same airflow level, it also makes much less noise. The difference ranges from over 10 dBA/1m at the high end to 4 dBA/1m at the low end. These are huge differences.

The Thermalright XP-120 makes better use of the airflow, besting the Zalman by a single degree. The difference is probably insignificant, but it is consistent across the range of airflow.

If the data comparison was changed so that the noise was the constant rather than the airflow, then we'd see the XP-120 running up to 5~6°C cooler than the Zalman at the same noise level. No matter how you look at it, the fan in the Z7700 is not as quiet as it could be.

3) Audio Recordings in MP3 Format

Zalman 7700 - 12V - 38 dBA/1m

Zalman 7700 - 9V - 32 dBA/1m

Zalman 7700 - 7V - 28 dBA/1m

Zalman 7700 - 5V - 22 dBA/1m

Zalman 7700 - Nexus 120 - 12V - 19 dBA/1m *

Thermalright XP-120 / Globe fan - 12V - 36 dBA/1m

Thermalright XP-120 / Globe fan - 8V - 27 dBA/1m

Thermalright XP-120 / Globe fan - 6.8V - 23 dBA/1m

Thermalright XP-120 / Globe fan - 5.4V - 20 dBA/1m

Thermalright XP-120 / Globe fan - 4.5V - 18 dBA/1m

Zalman 7000 - 12V - 39 dBA/1m

Zalman 7000 - 7V - 28 dBA/1m

Zalman 7000 - 5V - 22 dBA/1m

* See text box at bottom of page: 7700 Fan Swapping

HOW TO LISTEN & COMPARE

These recordings were made with a high resolution studio quality digital recording system. The microphone was 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 was 18 dBA or lower. It is best to download the sound files to your computer before listening.

To set the volume to a realistic level (similar to the original), try playing this Nexus 92mm case fan @ 5V (17 dBA/1m) recording and set the volume so that it is barely audible. Then don't reset the volume and play the other sound files. Of course, tone controls or other effects should all be turned off or set to neutral. 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 four of the article SPCR's Test / Sound Lab: A Short Tour.

CONCLUSIONS

The Zalman 7700-AlCu provides superior cooling performance than its predecessor, the 7000-AlCu, which still gives it a pretty good run for the money. The small but measurable cooling gain is obtained with no serious acoustic price, as the fans on these coolers measure almost identically for SPL. Given that the 7000 remains among the most popular of high performance, low noise HSF, a product that surpasses it has to be praised. They do sound a bit different, but whether one sounds louder than the other is difficult to judge. We suspect that with the Fan Mate set to minimum (5V) on both HSF, the 7700 would probably sound a touch louder for most listeners.

This noise level cannot be described as superbly quiet, however, even at the minimum 5V setting of the Fan Mate 2 voltage controller. We commented on this in our original 7000-AlCu 18 months ago, and we hoped that the 120mm fan would give us lower noise. The 7700 fan has not done that, though it has give us a slightly better noise-to-airflow ratio. It is possible that our Zalman HSF sample(s) were on the noisy side of their ¬Ī10% noise tolerance range, but we've had more than half a dozen 7000 series HSF through the lab, and they've all sounded pretty much the same.

The Thermalright XP-120, which is the only other 120mm fan CPU cooler at this time, is a tougher competitor to the 7700. Its multiple heatpipes and unusual design, combined with a separate conventional 120mm frame fan provide slightly better cooling than the 7700-AlCu with the same airflow, and at a much lower noise level. If we had set noise as the reference in our comparison chart (i.e., kept the noise constant rather than the airflow), the cooling advantage of the XP-120 would have been much greater than 2°C; it would have widened to as much as 4~5°C. However, that would simply have shown the superior noise-to-airflow ratio of the Globe fan over the built-in 120mm fan in the Zalman cooler.

The difference between the Globe fan and the integrated fan in the 7700 underline our point about the noise performance of the Zalman fans. Oddly, for a company that has staked its reputation on low noise cooling, Zalman fans have never been that quiet. Admittedly, this is related partly to Zalman's use of ball-bearing fans, which is almost mandatory in high heat applications such as power supplies and heatsinks.

Sleeve bearings rely on oil lubrication that tends to dry up sooner when subject to higher temperatures. When they seize, they do so quietly, without warning. Ball bearing fans last longer in heat, and when they go, they start screeching, getting louder and louder as they get worse. This is a kind of built-in safety warning for the PC user to explore what is going on, much like the screeching of worn brakes. For these reasons, ball bearings are almost mandatory in stock fans on heatsinks; most system integrators and OEMs do not accept sleeve bearings in HS or PSU fans. But they ignore the fact that ball-bearing fans are more easily damaged by physical shock during shipping. In practice, a good sleeve bearing or modified sleeve bearing such as the Hypro bearing in Panaflo fans lasts a long time even on a hot heatsink. (I've never seen a failure of any Panaflo due to heat damage in nearly four years with well over 100 units passing through my hands.)

Getting back to the 7700-AlCu, while it may not be the quietest or highest performing HSF in the market today, it is right up at the top, and the street pricing is only marginally higher than for the 7000-AlCu, which has always been a good buy. The XP-120 + 120mm fan is definitely more expensive, and because of the very high tension of the mounting system, actually more difficult to install than a Zalman 7000 series HSF. The fan integration is something a lot of people prefer for simplicity. And if the performance is good enough, and it fits in your system but you'd prefer lower noise, you can always swap the fan, as some SPCR forum members have done on the 7000 series. (See text box below: 7700 Fan Swapping)

As with all recent Zalman HSF packages, we have nothing to fault with this one (except the use of the too-common, environmentally unfriendly plastic). The new Fan Mate 2 is a genuine improvement, and the mounting hardware for the various processor types is well thought out.

Pros

* Excellent cooling performance
* 22 dBA/1m min noise is very good
* Great accessories package
* Excellent cross-platform compatibility
* "Tried and true" radial design
* Weight reasonable
* Pretty easy to install
* Probably better compatibility than XP-120
* Well priced for performance & package
* CU (all-copper) model probably performans better

Cons

* Still not as quiet as we'd like
* Outperformed by XP-120
* Probably too big for some systems
* CU model is too heavy

Much thanks to Sharka Computers for the Zalman CNPS7700-AlCu sample.

* * *

7700 Fan Swapping

SPCR Forum members reported success in replacing the fan in Zalman 7000 series coolers for a quieter 92mm fan, such as Joseph Clemente did in this thread: Zalman 7000A AlCu modded w/ CHROME FAN! SPCR reviewer Ralf Hutter also modded a Z7000 -- with a Nexus 92 fan. His technique involved replication of the screw mounts and a layer of silicone damping. Regular readers know that the Nexus 120 has become a SPCR reference fan for its extremely quiet performance. Sean Boyd, who worked on the thermal testing, decided to see whether he could perform a fan transplant on the 7700. The answer is yes, he could.


A "Boydstein" creation, but far from being a monster.

It was a quick mod for which readily available materials were used, namely, double-sided adhesive tape. Two layers about 1/8" thick in total were needed to raise the Nexus fan blades high enough above the fins. This is not ideal for any application in which the fan faces any direction other than straight up as shown in the photo above. You would not want to trust the tape to keep the fan secure on a vertically mounted motherboard. Sean is looking into high temperature double sided tape from 3M rated for high adhesion at 150°F long term.

One obvious acoustic benefit of the dual layer of double-sided tape was the mechanical decoupling effect. It was easy to hear that not only is the Nexus fan far quieter than the stock Zalman fan, in this application, it is quieter than when within its box frame. Even plugged straight into 12V, the SPL measured just 19 dBA/1m. The results of thermal testing with this mod:

MP3: Zalman 7700 - Nexus 120 - 12V - 19 dBA/1m

Fan @ 12V * 14 CFM airflow (measured on HS) * ~23°C rise from ambient * 19 dBA/1m

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