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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batpau19 - Friday, June 27, 2008 - link
They (ridiculously overpowered PSUs) *are* a joke, and yet I am buying one.Acoustics, modularity, warranty, etc. are all there. When you look at lower powered versions or other models, you consistently lose at least one of these qualities.
Point me in the direction of the 350 watt power supply that has a 3-5 year warranty, modular cabling, and silent operation and I'm sold.
Problem is, the @5$hat PSU makers just don't do that sort of thing.
hechacker1 - Saturday, June 28, 2008 - link
I agree. Even anandtech has used a kill-a-watt to determine actual load wattage.I can think of a couple things:
1. People recommend exaggerated PSU's because cheap PSU don't actually live up to their marketing. Illegal, but how can you sue somebody for poor efficiency?
2. Maybe peak load can't be accurately determined from the PSU use of power. I can imagine a loaded system that might need 1000w only for a short second, before dropping to something more manageable.
I do wish that Anandtech would investigate the issue. I personally bought an expensive Enermax PSU a long time ago, 400w, and it seems to handle all the latest hardware without any problem. But the reason I bought it was precisely because it was highly efficient and actually delivered it's rated wattage.
mindless1 - Saturday, June 28, 2008 - link
yet you don't need those things at all.If buying a lower wattage PSU it often has fewer leads so you don't have many if any to get rid of by modularly unplugging them.
If it doesn't cost 4X as much, it's easy to overlook it not having a 3-5 year warranty.
Silent operation is not a good thing by itself. Operation in response to temperature is a good thing. If you don't have good case cooling it shouldn't be silent. If you do, many PSU are easily ran close enough to silent (close enough it is something else you hear rather than a PSU pointed to the back of the system). However, all else equal you do still have a valid point in that if a unit is engineered capable of a higher load that means higher thermal load as well, meaning lower operating temp thresholds at an even lower system load than it's spec'd for.
Perhaps more to the point, in response to what the prior person wrote about reviewing PSU more suitable for 85% of the users, you don't really need reviews for that. You can randomly pick one of several name brand PSU in the $40 range on sale or with a rebate and do fine for that sub-200W peak consuming system. No need to be really picky about one then so long as you don't get one with an exceptionally loud or short lived fan. Just don't try to cut wattage too much, that $40 range will get a 500W PSU and that affords more margin even if overrated than a same quality tier 350W would.
bob4432 - Saturday, June 28, 2008 - link
guess the closest you are going to get is the antec ea series, but not modular. imho, for the price i would put up w/ the cables, but again, that is me.ahodge - Friday, June 27, 2008 - link
http://www.mgecompany.com/xg/products_powersupplie...">http://www.mgecompany.com/xg/products_powersupplie...This one has been around for a long time too.
I'm actually quite surprised that anandtech would mess up like this in an article. It's the first time I've noticed such a silly mistake like this. Usually you guys seem to really do your research. Oh well.
bob4432 - Friday, June 27, 2008 - link
makes me wonder if they are doing these reviews just to get extra product and advertisers $$$ or us? sadly, i am kind of leaning further one way as not many need a 1KW unit....zagood - Friday, June 27, 2008 - link
"...and now we have the first and only power supplies with heatpipe cooling."Zalman ZM750-HP
Zalman ZM600-HP
Zalman ZM500-HP
Thermaltake PurePower 350W Fanless Heatpipe
Not the first, and not the only.
Turas - Friday, June 27, 2008 - link
I mostly ike for how queit it is. I think they said at 500W it is only 17db. that is nice. If you look at a lot o the 5-600W power supplies they make a lot more noice as you get into the 400 + range. So even though the power is not needed it allows you to have a quiet machine since the power never really ramps up to the capacities.larson0699 - Friday, June 27, 2008 - link
This is definitely for the guy splurging on those 2 or 3 GTX280's.But most of the systems I build use less than 200W at load.
At 25% load any PSU bites on efficiency.
I like Zalman's concept, though. Just wish they'd cater to the majority.
Turas - Friday, June 27, 2008 - link
I too am wondering if maybe you had a faulty switch or something. silentpcreview also did a review of the unit and in their testing they did notice a slight difference to the better with the sounds turned on. They focus mostly on the acoustic side of things and even have sound recordings.I am glad to see to great reviews though from different sites. I think I am going to order one up now.