Zalman ZM850-HP and ZM1000-HP
by Christoph Katzer on June 27, 2008 12:00 AM EST- Posted in
- Cases/Cooling/PSUs
Fan Speed and Acoustics
The fans of both units stay at a just below 1000RPM for most of our load levels. The fans stays at these very low rotations under room temperature throughout our loading, only spinning faster when full load is reached. We have not seen anything like this before and need to congratulate Zalman for this approach. The heatpipes and 140mm fan are doing their job and cooling the unit very well, so there is no need for faster wind speeds. 1400RPM is the fan's maximum speed, but as we will see in the next graphic it is not perfectly silent.
Even though the previous graphic doesn't show how the fan accelerates before full load too well, the acoustic noise levels show the results. The fan spins just a bit faster as load increases, but it produces more noise than expected. There is absolutely no noise up to 600W of load; the PSU stays at a constant 17dB(A), which is quite low and not audible running in our acoustic chamber. If the unit is installed in a PC, users will not be able to hear it at all even with higher loads.
Now all you would need is to find two or three really quiet graphics cards and a CPU cooler and your silent system would be ready for this high-power, relatively quiet PSU. Without water cooling this will prove very difficult, since the coolers for today's graphics cards have to dissipate so much heat. Overall, however, both Zalman units deliver a very good performance from the silent point of view.
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jamesu79 - Friday, June 12, 2009 - link
I would like to bring the spotlight to various issues regarding this product and some of it's siblings (zm850-hp for instance). It suffers from a quite extreme variant of coil whining / squealing. Some sort of electrical high pitch noise that just drives you insane. I found a good video of it here: http://www.youtube.com/watch?v=mQa79pWC0OQ">http://www.youtube.com/watch?v=mQa79pWC0OQ
This seems to happen with a lot of the newer graphics cards, especially Geforce 260/280/285/295 and Radeon 4850/4870X2 etc etc. It also produces the same noise when you scroll a web page or copy a file to your hard drive. In fact, any hard drive activity triggers the same sound, albeit at a lower intensity, but still very audible.
When I first got this power supply and noticed this I tried to get in contact with Zalmans support. They kept telling me that they had forwarded my messages to their supervisors who, during a period of 4 months, haven't e-mailed me back. Not even once. Even though i sent follow-up e-mails twice a week. Or they would tell me to send e-mails to this other set of addresses (support1,2,3@zalman.co.kr), which never replied either. I did this 2 times a week for 4 months.
In other words, I was being completely ignored by their so called "support". They have been indefinitely postponing any type of resolution for this problem.
The issue gets worse when you realize that even if you RMA this product, since its a manufacturing fault; you would just end up with the exact same problem.
My honest recommendation to anyone thinking about buying this power supply would be to stay away. Or do very, very thorough research on if the rest of your PC components are compatible with this PSU in such a way that it doesn't generate squealing.
gwolfman - Thursday, July 3, 2008 - link
So if this is supposed to aid in cooling, where are the temp measurements? I'm quite disappointing not seeing any. I feel cheated since that's what's so unique about this power supply and you don't even test it. Boooo!BlandooV - Monday, June 30, 2008 - link
What exactly does SLI and Crossfire guarantee you with a PSU? Also, I'm with MadAd...where do the heatpipes take the heat to that makes it more efficient than heatsinks alone?MadAd - Monday, June 30, 2008 - link
Why? Just why?Heatpipes only move the heat from one place to another, its still got to be dumped out of the system some how.
schouwla - Saturday, June 28, 2008 - link
In Japan the cheapest price is ¥29,498 for ZM850-HPMerman - Saturday, June 28, 2008 - link
To quote your comment reply from the last PSU review:[quote]I find Ripple/Noise also very important but since nobody said a word I thought I could leave the graphics out and just add a comment. I always needed quite some time for the ripple graphs. I will add at least the comments again in the future and new models I get will have the ripple graphs again... alright? It's just there are not many people actually understanding what this topic is about and we need to still keep it accessible. No worries, I am working 7 years with power supplies and had several product managing positions in several companies. I know it's an important topic :)
[/quote]
If you are not leaving out important information maybe its the editor??? The power supply reviews on this site have degraded to the point of not worth reading. :(
Kanchenjunga - Saturday, June 28, 2008 - link
"It seems to be the same as the Antec Quattro which we tested last year. We recommended at that time to go for the smaller version with 850W because the 1000W unit didn't really bring many advantages with it. We will see later on in the tests if things are the same with these two units today. Even though we have 10 to 15 amps more on the 3.3V and 5V rails, the combined power of the 1000W unit is not too far away from the combined power of the 850W version. With the six 12V rails the same, there we have just roughly 200W more with the 1000W unit."Say what? It's not the same as the Antec Quatro which has only 72W of 12V power difference between the 850W and 1000W versions. And why do say the six 12V rails are the same when the label clearly says there is 240W difference?
Also which of these two models in the review did you test for the DC output graphs and which of the six 12V rails does your 12V rail graph show and why are your reviews increasingly useless?
anonymous x - Friday, June 27, 2008 - link
couldn't they make this giant thin smaller? My antec earthwatts 500 PSU, while delivering much less power, can actually fit in a micro-atx case without rubbing into my dvd drive.bob4432 - Friday, June 27, 2008 - link
not the one about the tps reports, the one about the fact that ~85% of the people using computers don't need more than a 400W quality unit? WTF is up w/ these 1KW units? hell, even 650W or higher?i have a decent rig - e2160 @ 3GHz (swapping out to a e8400 soon as i need a bit more cpu for some 3d modeling appes), 3GB ddr2-667, 15k u320, 7.2k 7200.10, 3850 512MB gpu, gigabyte p35-ds3l, 3x80mm fans, a 92mm cpu fan and a few pci cards, and at idle this system pulls an amazing 95W, at full load using 2 instances of prime95 and gaming it maxes out at 185-190W according to my kill-a-watt. i am running it on a ~$10 antec EA 380 unit that works perfectly. if i had another pci-e plug i am sure i could run cf fine if i wanted to.
my point - these 1KW units are kind of a joke for the majority of us but yet you reviewers just love them. why not review what the people need and actually make a review that will help people, the vast majority of people?
gwolfman - Thursday, July 3, 2008 - link
You forgot to do you TPS reports? Did you get the memo? I'll be sure to get you another one. :)