need advice on fanless PSU's side effects

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need advice on fanless PSU's side effects

Post by nick101181 » Mon Jul 30, 2007 4:10 pm


I recently bought a fanless silverstone 300w PSU. I currently have no case fans and am just using the stock processor fan. I noticed that now my pc is really really hot to the touch and even with the side panels off my pioneer dvd-rw drive ( and other drives) are so hot that the disc was almost untouchable when I finished burning a disc. I can understand the case being hot because the PSU touches the case but it's wierd that my drives are all seriously hot to the touch as well. I mean so hot you can only hold your finger for half a second or it'll burn you. Before I had a thermeltake 450 watt PSU that claimed to be low noise but wasn't. I forget which model but my case and components weren't this hot with that PSU even with the side panels on. I'm thinking I should either get a 120mm fan with 8.0 dba and install it into my existing case, or buy a new case that has two 120mm fan holes and use two fans. any thoughts or ideas on this? I like to leave my pc on for video encoding or downloading stuff,but I don't want the house to catch on fire though.


Edit: I also forgot to mention that I had RFI coming from the silverstone, when the pc is off I have no interference on my pc at all.

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Post by jaganath » Mon Jul 30, 2007 4:38 pm

you have no case fans and you're surprised your PC is hot? probably your noisy Thermaltake was evacuating case heat as well so you didn't notice before.

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Post by JoeWPgh » Mon Jul 30, 2007 5:11 pm

Put the Thermaltake back in ASAP!!!! NOW!!!
You've got to be very careful with a fanless PSU. You may or may not need a different case. You didn't mention what you're currently using. In any event, you'll need intake and exhaust fans to deal with the heat. Set the fanless aside, do some careful research, and design a system around it. Otherwise, you'll end up replacing everything at once.

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Post by nick101181 » Mon Jul 30, 2007 5:13 pm

I'm running an Asus k8v-se mobo with an AMD 64 3000+ processor, one 250 gig sata, one 120 gig ide WD drive,floppy,pioneer dvd-rw 110d and 106a with 1.5 gigs of 3200 sd-ram.

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Post by Confucius » Mon Jul 30, 2007 5:31 pm

If a silent computer was as simple as removing all the fans, then would we really need this website? The fact is that your system generates a lot of heat and it needs to be managed (eg, removed from the case).

The easiest, cheapest way is simply blow a lot of air through it but that's loud. The hardest, most expensive way is to buy a perforated case, sitck huge heat sinks on every heat generating source, and have a lot of ambient air movement.

Right now it sounds like your case is essentially sealed off and all the heated air is being trapped inside. What you are doing now is bound to fry your CPU and MB eventually and probably take out a few other things with them.

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Post by JoeWPgh » Mon Jul 30, 2007 5:35 pm

Don't use the fanless PSU until you get a 120mm in there. While an 8dba fan might sound nice, it likely won't move enough air. Check the recommended fan list.

Do a google for SpeedFan and install it The readings you get from that will be important for getting advice from people who know far more than me.

The risk of burning down your house is probably slim (but theoretically there). But the odds of completely frying your computer (fanless PSU and all) are pretty high.

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Post by Redzo » Mon Jul 30, 2007 5:41 pm

As everyone else said, put some fans in that pc ! You will fry it and risk is that your data and files could go with it so...backup.
Just removing fans and buying fansless PSU is not the way to go. Heat is still there but now it has no way of escaping....! Heat kills computer components, thats why ppl put fans in to begin with...And you have none.
You do the math.
How much is your computer worth to you (and stuff on it) ?

Plese do read around forums, there is a wealth of info, how-to's and pics on how to silence a system safely !

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Post by Shadowknight » Mon Jul 30, 2007 7:50 pm

You just have to be careful with designin the system:

My system has a Nexus at 650rpm blowing on the Phantom I have, and it keeps everything nice and frosty. I still use an 80mm fan on my VGA heatsink (Nexus) but it's undervolted to the point where I can't hear it. I also run the system fan at 650rpm, and everything's fine.

In my old (non-P180 case) I had the same setup (minus a separate fan to blow on the PSU) and everything ran fine... but you need SOME airflow. Even a tiny bit can be enough. One time while playing around with my computer, I accidentally jiggled-loose the power cable to the fan controller. No-airflow equalled almost burning to the touch case and everything auto-shut down. On the otherhand, the 650rpm Nexus kept everything fine.
[size=75]Asus P4C800 Del., P4 3.0 Northwood w/Scythe SCNJ-1000 Ninja (fanless), Antec P180 black SPCR edition w/Acoustipack V.2 Deluxe; BBA X800 XT PE w/Zalman ZM80C-HP and 92mm Nexus; Samsung P80 120gb Smart Drive 2002 on foam; Raptor 74gb (turned off); Antec Phantom 350w; 2x120mm Nexus @ 670rpm, diNovo keyboard, Thanko Silent Mouse[/size]

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Post by nick101181 » Tue Jul 31, 2007 2:11 am

I noticed that the 120mm fan I wanted to get was 800rpm, would that be sufficient cooling given the amount of rpm? Should I install it as an intake fan or an exhaust fan?

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Post by JoeWPgh » Tue Jul 31, 2007 12:41 pm

nick101181 wrote:I noticed that the 120mm fan I wanted to get was 800rpm, would that be sufficient cooling given the amount of rpm? Should I install it as an intake fan or an exhaust fan?
I'd go with a Nexus 120mm. It's rated at 36.86 CFM/1000 rpm/22.8 dba. I think that's the least you could get away with. Definitely use it as an exhaust. If it brings your temps down enough, you could always get a fan controller to slow it down. But without a fanned PSU and no other case fans? This may still leave your rig a little warm, but it will at least give you some breathing room. If you have an available intake port, get 2 of them and dial them down.

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Post by ronrem » Tue Aug 07, 2007 1:53 pm

All of the above and more-----

First.....think. Thinking is always step one. The lack of a FAN does not mean a PSU does not create HEAT. A good CPU cooler ONLY pulls the heat from the CPU to where it can better be extracted by the case airflow. In your situation--the final step---getting the heat out of the case,is missing. You have an oven that CONTAINS and ACCUMULATES heat. Bad news.

A Fanless PSU to really do it's magic should be well vented,should be isolated from the heat of the CPU and Vid card. It should have airflow-but that airflow should be relatively cool.

Bolting it to the OUTSIDE of the case is a solution,though that takes some planning.

Having a seperate chamber or ducting are good options. Either does require you THINK out the airflow.

A fan creates pressure. It can blow into the box-or out from it. An exhaust fan will create a draw from all openings. An intake fan will force air out all openings. Look at where the fan is-and where the openings are and you get the ideas of where the airflow goes. You can change the path by expanding or eliminating an opening. You can use ducts or deflectors to alter a path. Fan placement can be changed.

There ARE a lot of clever and creative ways to really make best use of a fanless PSU. Unfortunately...hardly any commercial cases bother to do anything much to optimize for fanless.

An unconventional layout (homebuilt) case can definitely optimize cooling a fanless quietly. I've seen or sketched up quite a few things.

For a Silencing Newbie....the best bet is to get SOME case fan airflow-and then do more homework on the details.

8 db fan? The fact is there's a LOT of ways to measure decibels,you have ambient room noise. Is 8 db fan noise minus the room noise? Probably...since theres no mike/meter than can even measure a total 8 db noise level. Is it measured at 12",at 36" at 60" ? that makes a big diff.

I go more by RPM. There's no ambiguity. Only the crappiest fan makes much noise under 1000 rpm. At 2000 rpm,even the best fan is not very quiet. A big deal is how well a fan CAN be run at low RPM.
At stock speed....there's nothing very special about a Yate Loon,but if you undervolt it to run under 800 rpm its great.

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