The Zalman Twins: 9500 & 9700 Air Tunnels
by Wesley Fink on February 19, 2007 12:40 AM EST- Posted in
- Cases/Cooling/PSUs
Noise
For many enthusiasts upgrading cooling the goal is maximum stable overclock, and they will live with the inconvenience of a louder system. For other users silence is the most important factor, and these users will forgo maximum overclocking if this increase system noise levels. In general the Zalman 9500 and 9700 can be considered very quiet, but performance of either cooler is not standout against the competition - at least where noise is concerned.To test idle and load noise levels, the Zalman fan controller was used to dial in the lowest and highest fan speeds the fan could achieve. Lowest speed results are reported as idle and high speed results are reported as stress noise. These are procedures that we plan to use, if possible, in future CPU cooler reviews. Both sets of results will be reported if there is a significant difference in low-sped and high-speed noise.
There are virtually no power supplies that do not have a fan. While Zalman and a few others do make a few expensive fanless power supplies, we have not seen a fanless unit larger than 500W, or one that would be used for seriously overclocking a system. With that in mind the noise level of the system with all fans turned off except the power supply was measured. The power supply used for the cooling test bed was the OCZ PowerStream 520, which is one of the quieter of the high performance power supplies. The noise level of the power supply was 38.3dB from 24" (61cm) and 47dB from 6" (152mm). The measured noise level of the test room is 36.4dB, which would be considered a relatively quiet room with a noise floor slightly below the OCZ PowerStream 520 PSU.
Measured noise levels in this chart should be considered worst case. Measurements were taken with an open side of a mid tower case 6" from the open HSF and 24" from the open HSF. Real world would be a completely closed case with a further reduction in noise.
Zalman, silence and low-noise all go hand-in-hand in the mind of most computer users, so Zalman is expected to be the standard against which others are measured. Put another way, noise is an area where Zalman is expected to top the charts. The Zalman 9500 and 9700 both exhibited noise levels below the system floor at idle speeds measured 6" and 24" from the cooler. This is typical performance with most of the heatpipe towers we have tested in recent weeks.
However, when pushed to the highest speeds available under stress conditions, the noise levels of the 9500 and 9700 were average at best. Neither Zalman was particularly quiet at high speed, and the 9700 was one of the noisiest coolers we have tested in the lab at 2800 RPM - 3db is twice the sound energy of the Tuniq Tower 120 at high speed and almost as loud as the Monsoon II Lite which is plagued by buzzing and clicks from fan switching. On low speed the 9500 and 9700 are very quiet, as are most heatpipe towers, but higher fan speeds yield much higher noise.
The measurements we made are also what you will get with either Zalman, since the fans are custom and embedded in the Zalman design. Zalman did not design the fans to be replaced with other 92mm (common size) or 110mm (Uncommon size fans). All-in-all the Zalman 9500 and 9700 were competitive with other tested coolers in noise levels, but they were not stand-out in any way. This is a reflection of how far the competition has come in addressing noise concerns in the PC environment.
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Avalon - Monday, February 19, 2007 - link
Keep up the good work. I'm enjoying watching the list of coolers you guys review grow and grow, and I think it's great that you'll be doing the Scythe Infinity and Ninja soon. I know I've mentioned this before, but I still want to see the Coolermaster Hyper TX if you guys can get your hands on one. Reason being is it looks as though it provides excellent PWM area cooling...which brings me to my next question...Have you guys considered throwing in PWM area temperatures? Some coolers are great at cooling the CPU, but awful at providing air anywhere else...and PWM cooling can help with stability.
Wesley Fink - Monday, February 19, 2007 - link
We agree that PWM is an important consideration, and it is something we will likely visit in a future article. Most of the top motherboards these days use passive sinks on the power transisitors and northbridges, but they also come with cooling fans for use with water cooling and HSFs that do not provide good cooling for board components. The 680i has such a fan and we use it in our testing to try to remove the variable PWM air flow and temps as a performance factor. Of course, that avoids the question by removing the variable, rather than answering it. We will try to address this in some future article, but for now we have a lot more coolers waiting for tests on our standard test bed.acivick - Monday, February 19, 2007 - link
I didn't see it listed anywhere in the review, but I'm assuming that the included thermal compound was used, at least for the 9500/9700. If the same compound was not used for all coolers, they should be retested, as it's not a valid test. Using the same compound on each would make it more of an even playing field and would thus be testing the performance of the cooler only.For instance, MX-1 is supposed to be much better than the stuff Zalman provided, giving a 3-5C decrease in overall temperatures.
Wesley Fink - Monday, February 19, 2007 - link
We use the thermal compound that comes with the cooler in most cases. If it is just a little packet of cheap thermal compound we use our standard, which is a silver colored tube thermal compound of pretty decent performance - not something exotic like MX-1.In the case of the Zalman 9500 and 9700 we used the Zalman Thermal Grease. Before replying to this question I tested the Tuniq Tower 120 with the Zalman Thermal Grease. Results were all but identical to the tests we ran using our bulk silver colored compound.
Over the years I've used many thermal compounds, and if you use a quality product and apply it properly the results have been similar. I hear what you are saying about a 3-5C difference with MX-1, but I certainly have not seen those kinds of gains with any thermal grease. I can also point you to a serious review that shows toothpaste and Vegemite with superior performance to Arctic Silver 5. At some point in the future we might take a closer look at the impact of thermal compounds on performance, but for now I am confident our current test methods are not introducing new variables with sloppy choices of thermal compound. We are prudent in our choices, but not maniacal.
JarredWalton - Monday, February 19, 2007 - link
Except a lot of people use whatever comes with the HSF. Wes would have to explain what thermal compound he's using, but I would assume he's sticking with the included stuff for each HSF where possible. If nothing is included... well, I don't know what he does there. :) Basically, though, I don't think retesting is in order unless he's using high-grade stuff on HSFs that omit the inclusion of a compound.VooDooAddict - Monday, February 19, 2007 - link
I agree that he should make it clear though what he's using.Using the shipped compound with these units would be preferable from complete product a review standpoint. As it stands there's no mention of his cleaning and reapplying new compound either. From a simplicity standpoint of reviewing and a better comparison of coolers, it would be easier to just use one compound for all the coolers to reduce cleaning time and variables.
ozzimark - Monday, February 19, 2007 - link
umm, my 9500 looks NOTHING like that base :-Xhttp://www.eclipseoc.com/image/cooling/zalman%20cn...">click for pic!
dev0lution - Monday, February 19, 2007 - link
Good info. I was leaning towards getting the 9500 since I don't think my 7700-alCu will fit on the eVga 680i board I haven't got around to installing. I might consider getting one of the alternatives now, seeing as how it doesn't look like the zalman's are worth the price premium.Fishie - Monday, February 19, 2007 - link
The Tuniq is 54dBs while the 9700 is 57dBs. Twice as loud? Wouldn't twice as loud be 108dBs? Not to mention the 9700 is quieter than the Tuniq at 24" away.
Wesley Fink - Monday, February 19, 2007 - link
3db is twice the sound energy, since the db scale is logarithmic. At one time twice the energy was considered twice as loud, but recent research shows 6db to 10db increase to be perceived by the human ear as twice as loud - depending on whose study you read. I have stated this in past reviews. To be more precise I changed the wording in the review to twice the sound energy.