Are fanless PSUs a waste of money?

386-sx-33 · Post by **386-sx-33** » Thu Nov 18, 2004 8:18 am

Fanless PSUs are extra expensive but silence is worth some $ so maybe it's a good deal afterwall.
Or not?
A PSU with fans acts as a casefan; so getting the hot air out of your case.
With a fanless PSU you are forced to place a seperate fan.
So first you pay $100 extra to get rid of the fan and then you get $20 extra to get a fan

Or am I overlooking something obvious?

Uberapan · Post by **Uberapan** » Thu Nov 18, 2004 8:44 am

If you watercool, you get most of the heat out of the case that way.

You can keep the case open and get rid of the heat passively.

I have the silverstone fanless 300W, and the difference between that and my Zalman 300W was enormous.

Tibors · Post by **Tibors** » Thu Nov 18, 2004 1:54 pm

If you have a modern high power system and use only your PSU for system exhaust, then the chances are fairly high your PSU will turn into a big noise source. You try to cool it with relative hot air, so your fanspeed goes up. Plus all that air is pushed between the PSU components causing a lot of turbulence noise. To prevent this I see three options:

Add a case fan so not all the heat has to go through the PSU. Your PSU fan will turn slower, but you still get some of the turbulence noise.
Become as creative as Bluefront. Search the forum to see what the benefits are.
Buy a fanless PSU and a case fan. This eliminates one fan from option one. The one that made the most noise.

P.S. I think option one is currently the most common setup. So most people don't have to add a fan if they buy a fanless PSU. It is already there.

brad · Post by **brad** » Thu Nov 18, 2004 6:24 pm

If the fanless PSU is more efficient than a standard PSU, then you get less heat. You come out ahead even if you do need to add a fan! Also saves the hassle (and danger) of opening the PSU to swap out noisy fans.

lm · Post by lm » Sun Nov 21, 2004 4:49 pm

Tibors wrote:If you have a modern high power system ...

If you have a modern low-power system, then a fanless high-efficiency psu will cool itself really easily passively.

Many fast systems using undervolted or less power hungry cpus and graphics cards can be drawing much less than 100W DC. Combined with a psu that is over 80% efficient, we get much less than 25W heat produced in the psu, which can easily be cooled passively by a decent fanless psu.

Tibors · Post by **Tibors** » Mon Nov 22, 2004 12:14 pm

lm wrote:If you have a modern low-power system, ...

Then you don't need a fanless PSU, unless you have extreme low ambient noise. Low power systems can be powered by standard PSUs modded with a Panaflo L1A.

Talz · Post by **Talz** » Mon Nov 22, 2004 2:20 pm

Not everyone wants to open up their power supply and mod it. But it's not that hard to find a quiet lower power air cooled power supply if you try.

It's definately an extreme product though, most suited to systems with water cooling that have at least a moderate amount of airflow already. Zalman's upcoming external fanless will be much more air cooling friendly though and an exception to that rule.

Mats · Post by **Mats** » Wed Nov 24, 2004 1:51 am

It's to bad that there's no separate PSU available like the 180 W Shuttle Zen. I don't know the different wattage numbers for it but I guess it gives more than the 120 W does.

...and what happened to those piezoelectric PSUs? 100% efficency, no heat (of course), no noise (that we can hear), smaller... ..I'm still waiting! Any news?

thegonagle · Post by **thegonagle** » Wed Nov 24, 2004 1:27 pm

Mats wrote: ...and what happened to those piezoelectric PSUs? 100% efficency, no heat (of course), no noise (that we can hear), smaller... ..I'm still waiting! Any news?

100.00% efficient voltage transformation and AC to DC rectification at room temperature? (BS_flag=Yes) And affordable to a sufficient mass of PC enthusiasts? Until I learn more, I'll say that sounds like vapor-ware to me.

Edwood · Post by **Edwood** » Wed Nov 24, 2004 2:41 pm

Stay far far away from SileneMaxx products.

I had a ProSilence 350, it died in less then 6 months. It was stilll under warranty. I RMA'd it, shipped it to SilentMaxx. They agknowledged receipt, and I never heard from them again, despite my many phone calls, letters, faxes, and emails.

Looks like SilentMaxx USA has pretty much disappeared.

Beware of SilentMaxx.

-Ed

8300ati · Post by **8300ati** » Sun Dec 12, 2004 6:01 pm

I think that they are a waste of money because if you think about it what is the point of putting a power supply without a fan when you need one anyway for the case. Also the fan on the power supply is on the inside of the case so it will be almost inaudible. Fanless power supplies are notorious for burning out after a short time.

Slaugh · Post by **Slaugh** » Sun Dec 12, 2004 7:52 pm

If you want to avoid heat buildup inside the case, you can put the fanless PSU outside the case. That's what I'm planning to do when my Phantom will be shipped. Combine that with watercooling and you have a very (but still expensive) system.

burcakb · Post by **burcakb** » Sun Dec 12, 2004 11:45 pm

I'll let Ralf comment on fanless. He actually did - to my rig in my sig. Considering that it's the point he chose to comment on says a lot IMO. I completely agree with him on this issue

lm · Post by lm » Mon Dec 13, 2004 2:03 pm

thegonagle wrote:
Mats wrote: ...and what happened to those piezoelectric PSUs? 100% efficency, no heat (of course), no noise (that we can hear), smaller... ..I'm still waiting! Any news?
100.00% efficient voltage transformation and AC to DC rectification at room temperature? (BS_flag=Yes) And affordable to a sufficient mass of PC enthusiasts? Until I learn more, I'll say that sounds like vapor-ware to me.

Even if it's just something like 95%, then a high-power system consuming 200W DC will produce 10W of waste heat in the psu. 88% is already achieved (phantom), and that's probably not at any limit of what's possible.

10W can be dissipated with quite small heatsinks so the psu can be tiny.