Laptops PSU do not have any fan.
They are probably less powerfull, but would it be possible to run a desktop computer with such psu?

yes. I thinks the only one CPU+mainboard can run in this PSU is this one ( VIA EPIA M) @ http://www.viamainboard.com/product/epia_m...otherboardId=81


maybe possible this one http://www.viamainboard.com/product/C3M266...therboardId=101 ,not sure

My Laptop is running a 0.18microns 1.1gHz PIII, a combo dvd/cd burner, and obviously a screen.

Those components should require a lot of power, then I do not get why a desktop computer could not be powered by a laptop psu. Anyone has an explaination?

From c't 25/2002, some power consumption tests:

- Pentium 4, 3.06 GHz, on ASUS P4PE & Radeon 9700:

Idle: 99 Watts
Full load: 184 Watts
Time for video transcoding test: 8.4 minutes
Power consumption for that: 22.6 Watt hours


- Athlon 2400+ on Epox 8KT3A+ & Radeon 9700:

Idle: 121 Watts
Full load: 163 Watts
Time for video transcoding test: 10.3 minutes
Power consumption: 24.0 Watt hours


- Toshiba Notebook with Pentium 4-M, GeForce 460 Go & display:

Idle: 34 Watts
Full load: 67 Watts
Time for video transcoding test: 13.2 minutes
Power consumption: 13.7 Watt hours


- 4MBO Notebook with Mobile Athlon XP 1800+, integrated graphics, display:

Idle: 35 Watts
Full load: 74 Watts
Time for video transcoding test: 14.2 minutes
Power consumption: 17.7 Watt hours


As you can see, there's quite a difference. Desktop processors also have a much higher leakage current (P4 Northwood core: 30 W in Stop-Grant-mode aka. "HLT" mode).

Yes, but my laptop processor is a regular desktop processor, not a mobile one.

I checked my AC unit on the laptop, and it's a 60W one, wich means that 60W is enough for a pIII, screen, small harddrive and cd burner.

And why not multiple PSU?

For a server it won't be enough, but for a normal desktop use?
I'm asking because to my ears "quiet" desktop psu are perhaps quite but not silent at all.

Desktop PSUs have to be cheap. That's why inefficient components are used. Notebook PSUs are more efficient, because the price can be higher, and heat is an issue. But there are already silent desktop PSUs available (passive cooling or ultra-silent fan), of course, they easily cost more than 100 Euro.

For example:
http://www.siliconacoustics.com/powersupplies.html
185 or 230 $

I already have a "quiet" psu from Q-Technologies. It was about 60€. It's quieter than my previous one, but far from silent.

I'm happy to know that there are fanless desktop psu, but unfortunately, this one cost a lot...

An overview of silent PSU's is here: http://www.hartware.net/media/reviews/253/...teil_charts.gif

The Zalman ZM300A-APF was the best; ultra-silent opration and a price tag of 90 Euros.

Unfortunately I do not believe in ultra-quiet things. I have some in my desktop, and to my ears it's still noisy.

Perhaps we should compile a list of quiet and silent ressources for computers

Hmm.. have you even looked at that chart? Their testing room had a reference noise level of 22.9 dB/A, and a PC with passive PSU cooling has 24.2 dB/A. With the Zalman, it's 26.8 dB/A. I think this is really very quiet.

I think you've been "damaged" by the usual advertising methods of PSU makers: Everything is called "silent" these days, to make it sell better. Double ball-bearing fan, temperature controlled, yadda yadda... and mostly, it's about as silent as a death metal concert. But these tests show that it can be achieved even with active cooling, if your pocket is fat enough...

Yes, I think that I've been disapointed by the products I'm using.

My psu is advertised as 27dB, and to me it's noisy. (QTechnology)
My cpu fan is advertised as 19?? (http://noiseblocker.shops.at12.de/servlet/de.at12.shop.servlet.ShowProduct;jsessionid=aaa9jBDd1lTrDd?id=70117&cs=true)

Those parts are more silent than the previous ones, but that is not silent at all.

Perhaps it's only possible to get really quite components if you are willing to pay a lot...

The only thing that really featured a big improvment compared to previous component is the hardrive: I previously had a 5400rpm one from Ibm, and I now have a Barracuda IV. But this is not silent neither...

I have a Zalman ZM300A and I have to confirm Gabriel suspicions. It is quite quiet, but it is not silent.

Maybe it depends a lot on your case and how many other fans you have (and so on), but it is still the noisiest part in my computer.

It is the most quiet (affordable) PSU I have found, but I really would like something less noisy.

Another overview, which rates the Nexus NX-3000 a bit quieter than the Zalman ZM300A-APF. I think they imply that a quality low-noise power supply (Zalman, Seasonics, or other), modified to use a Panaflo fan instead of the stock fan, would be quieter still than the Nexus, although heat could become an issue. The Nexus, Zalman, and Seasonics all run the PS fan at low-RPM (~5V) unless the machine really heats up.

I think a Panaflo-modified, low-speed fanned PS, with some noise-absorbing material placed behind it on the wall, could truly achieve near-silence (not near-noisiness, like other "silent" components).

Out of the box, the Seasonic PSU I had definitely was not quiet. It even produces a very low volume HF-noise, when deactivated.

Not really what you expect after a review on this site: http://www.silentpcreview.com/modules.php?...artid=28&page=1