How To duct A Cpu?

i was wondering how can i duct my cpu i saw in other thread something about ducting but it didnt tell how

 

The idea is to supply fresh air to your cpu fan directly - not using recycled warm air from inside the case.
The most straightforword method is to cut a hole in the side of your case where your cpu fan would be roughly located and to use a big pipe to direct air for the fan.
I have seen a fan mounted in this hole to force air at the cpu fan.
Maplins sell a kit that connects your front case fan to your cpu fan to save cutting your case up.

 

You can use any kind of piping, vacuum tube, even a bit of cable sleeving (if its the really wide stuff).

I wouldn't go for connecting it to the front fan, cause that would mess with your airflow so much!

 

removing a side cover and putting a home fan is probbably the WORSE idea you can reccommend.

 

It gets air in there, yes, but....

- A whole load of dust is blown in with the air, increacing the risk of a fire.

- The magnetic field created by an electric motor (permenant magnets and an electromagnetic coil) is massive, especially for one powerful enough to drive a fan. Bad news for floppies and over prolonged periods, bad for hard drives too.

- with the side of the case off you are also more likley to spill somthing into the case, or generally damage the internals of the machine. Thats what a case is for : to protect the machine.

 

Dust gets in yes. But if you have EQUAL amount of air flowing IN & OUT dust is minimized such that you only need to clean ever few months.

 

Maybe I should go call Dell and tell em to ductape 16"fans to their cases from now on.

 

That helps.

But it also helps to arrange some cardboard sheets so that exhaust from the HSF is sucked out of the case by a case and/or PSU fan instead of being sucked into the HSF intake and re-circulated.

The side fan and ducting I arranged on a stock AMD XP 2500+ cooler was as effective as a Zalman CNPS6000-Cu cooler in terms of reducing CPU temps.

 

it place I worked had cooling towers where water would cycle through
kinda like a radiator, but not. .I guess water-cooling
tubes running through the coils. . .
what about compressed air, very low pressure at key points
clean air,mind you. . oil water free.. . . .?

 

I've been running open covers for years and they don't get dusty hardly at all.

 

Well, I'm glad I didn't have time to read THAT post.....

Running a computer with an open cover permenantly and there is no dust? I get dust with closed covers and filters. How does that work? Perhaps in a clean environment, probably not an average house though.

 

how to build my cpu duct

I have bought the MAplin Duct, to try cool my P4 3.0Ghz Prescott processor down.....

However, my heavy load temps are not dropping, instead they are rising slightly ..... (touching and passing 70 degrees celcius)

does the fan on the other side of the duct need to be running at the same speed as the CPU fan?

what happens when this second fan runs at low speed, say 1000-1500 RPM, can this create a problem ?

i have used the duct, connected it straight onto the CPU stock cooler (I used 2 elastic bands to get it holding position onto the cooler) and the other end going outside the case, to the front, having an 80mm Antec fan blowing air into the duct.

What am I doing wrong here?

I have 3 case fans (front, back, side-panel) and 1 psu fan that also blows air into the case, should be enough cooling no?

 

Re: how to build my cpu duct

Ouch. That's a bit warm!

I doubt that the rpm is much of a factor. The amount of air the fan pushes is more important. Two fans running at the same speed can push quite different amounts of air.

My guess is that you want to have the higher-capacity fan at the entrance to the duct so that the fan at the CPU end has all the air (and more) that it can use.

Not necessarily. It depends on the volume of air moving through the case, the temperature of that air, and the path of the airflow.

Best way that I know of to check for effective air flow is something I picked up from AMD's white papers on the topic. (Go here if you want to find some of them.) Check the temperature rise of the air going through the case -- specifically, the difference between the temperature of the air entering the case (ambient temperature) and the temperature of the air coming off the CPU heatsink. If the rise is more than 7C, either you're not moving enough air through the case, or the airflow is bypassing the CPU and its heatsink.

The Maplin duct should prevent that -- if the airflow is right. But there's got to be someplace for the air to go once it exits the duct and passes through the CPU's heatsink. The PSU fan blowing into the same area may be creating back pressure that interferes with that flow.

A Radio Shack electronic indoor-outdoor thermometer works fine for checking airflow temps, and they're not expensive. Put the thermometer shell by the computer case air intake, so that the "indoor" sensor reads ambient temps. Put the remote probe in an appropriate place inside the case.

One of the benefits of ducts around the CPU heatsink is that (if they're properly arranged), they will prevent air that's been heated by the CPU heatsink from getting sucked back into the CPU fan and going around a second or third time. The warmer the air going through the heat sink, the worse the job of cooling that it does. See my earlier post for the results I got in my case.

Another thing: make sure that the case and PSU fans in the immediate vicinity of the CPU are exhaust fans, so that the heat thrown off by the CPU gets sucked out of the case. If you're using an ATX board in a standard tower case, your PSU fan should be taking air out of the case. Blowing air in at the top rear of the case is likely to cause a lot of turbulence or back pressure that destroys case cooling efficiency.

AMD suggests that you should have greater exhaust fan capacity than intake fan capacity. The reverse of that is a little like pushing on a rope. Not much happens. Or think of it this way: the object of the exercise is to carry the heat out, not blow air in. The only reason you would want an intake fan is so that the CPU and case exhaust fans aren't starved for cool air to carry the heat out with.

 

Hi Rob,

thanks for your detailled feedback.

I have done some further testing yesterday.

My biggest concern is the alignment and speed of the fans. My Antec case has fan regulator power cables (PSU controls the speed), but also my Intel motherboard has 2 additional fan connectors (ASIC). I have a fan monitor and temp. control unit installed, and i have compared both fan speeds and found the fan will run at a higher rpm when connected to the PSU fan-only connectors.

Therefore i have changed my fan cooling configuration to the following:

1. PSU fan is blowing air out of the case (80mm), but also has a 120mm fan that sucks air out of the top of the case, just above the motherboard (not straight above the cpu though)

2. Antec 80mm fan sucks air out of the case at the back, connected to the Fan-Only connector (PSU)

3. Antec 80mm fan blowing air into the case at the front-bottom, connected to the Fan-only connector (PSU)

4. Coolermaster 80mm fan in the sidepanel, blowing air into the case directly on top of the videocard, connected to the motherboard fan2 connector (ASIC)

5. Antec 80mm fan blowing air into the duct-end, which is located in the 5 1/4 drive bay, sucking cool air in to the duct from the front of the case (dust filtered), connected to the Fan-Only (PSU)

---------------------------------

Now, i have quite alot of temperature measuring points in my PC:

1. CPU
2. Motherboard zone 1
3. Motherboard zone 3
(mobo zones: see http://www.auij64.dsl.pipex.com/)

4. Case Temperature
5. Video Card Heatsink Temperature
6. Hard Disk Temperature

With changing the configuration, i have noticed that the zone 1 temperature stays under the recommended 50 C. But Zone2 can rise up to 58 C. Intel recommends not to go further than 55.

The CPU temp has dropped a bit with the Duct, when i run an intensive cpu test program (xlrdib.exe or somethign like that, some visual demo with rotating background and large "balls" reflecting in the middle) the CPU temp doesn't go over 65 C, but when i play a 3d game i have noticed it may go up to 67-68 C.

At this "high load" the fan speeds are as following:

1. CPU fan: 3000 rpm
2. PSU fan: 1400 rpm
3. case fans: 1400 rpm
4. side-panel fan: 1300 rpm

I like to create a diagram of how everything is installed and how the air flows, but need some more time to do this.

The video card temp may rise up to 65C. The hard disk temp also may rise up to 55C, I noticed.

Any suggestions ?

thnx.

 

Not very pretty but this celeron d 2.93ghz is folding at 90% and is running around 38 degrees C. for CPU temp.

of course I run it with case side on!!

 

Not pretty, but obviously effective. I also note the cardboard ducting you've used to direct HSF exhaust heat out of the case and away from the CPU fan. My experience suggests that's likely to be the more effective of the two mods I see in your photo.

 

Given your difficulty in getting your CPU temps down, I begin to wonder about the thermal interface between your CPU die and your heatsink. Perhaps inadequate or improperly-applied thermal paste? Too much of it?

But it's hard to draw any conclusions in this area. It would help if you knew what temperature rise you are getting in the air that flows through your case. See my previous post on that topic.

Those case fan rpms are low to move very much air with an 80mm fan. The rear exhaust fan is critical -- it's the one that removes much of the CPU's heat from the case. An 80mm fan at 1400rpm isn't likely to move as much as 20CFM (cubic feet per minute). You might consider swapping the rear exhaust fan for one that provides a higher capacity.

The downside of such a swap will be more noise. The faster a fan spins, the more noise it makes. But you should be able to find an 80mm fan that moves more than 30CFM at less than 30dbA noise.

You might also try disconnecting the case side and front intake fans (one at a time) to see what contribution they make to your temperature reductions. You might find that the front intake fan doesn't contribute much besides noise, or the side intake (blowing where it is) is causing turbulence within the case that interferes with airflow in critical spots -- perhaps by causing a high-pressure zone at the heatsink exhaust that restricts airflow through the heatsink.

 

I don't think that ducting is more effective then the rest you can do - cables clipped away, really gone, two 12mm in front + in back + 1*40mm in front + a zalman or whatever cooler on your cpu and good psu)

I challenge everyone to get a cooler system with ducting overall cooling I mean.

mine cpu idle 41-44C (at 1300rpm is silent, very silent) at 3000rpm it will be 38-39C
at full load it gets 50-55 (at 1300rpm silent)
case is 33 (1300 rpm)
hdd is 35

and then again, it must be silent like 25db (the only thing you hear is the psu 12mm fans)

my specs are P4 - 3.4 550

 

ohh yes, when my digital camera is back like in its old days I will post some screenies, I owe it to you guys.

 

whow nice mod i see i have arrenge a new case wich is ducky brand (cost me 40) and already hada a duct that pull out the heat of the procesor, since it pulled heat away a i reversed the fan of my hsf, so it wnt down 3 degres,
i was amused 3 degress just for a duct pulling all air out so i did my own mod i mounted a panaflo 92 mm on the sidevcover were the grill of the video card is and cooled down my entire system


now my temps are
duron 1400@1533
before after
cpu 50 degrees 45 degres
system 24 degrees 20 degrees
hdd 35 degrees 25 degrees



this is my case

 

Wow Optimizer - you can stock your beer bottles in your case - that chilly!!!

RobM - thnx for the feedback - changed thermal solution between CPU and heatsink with AS5 (after cleaning properly) and this has really lowered my temps... as for the fan speeds, maybe i try to replace them with 120mm ones in a while... for now i'm happy enough...

kvla - 20C case temp? do you have central heating at all?

;-[]

 

what do u mean by central heating?

 

Boy I tell ya, Intel motherboards and the worrying over heat, is about to make me start drinking!

My sys is as follows
Intel D865PERL Motherboard
3.0Ghz Prescott
1gig Kingston pc3200
80gig harddrive
160gig hardrive
Nvidia FX5200

120mm intake fan upfront 2150rpm
120mm exhaust fan 1900rpm
2 80mm exhaust fans staked ontop of each other exhausting out the side of case, inline with cpu
Stock HS and fan 2600rpm

My temps are idle/load
CPU 35C/ gaming 46c to 50
Zone1 31c/ gaming 40c
zone2 33c/ gaming 46c

Recently I have started encoding movies and my temp are shooting out the roof, cpu runs about 135f and zone2 keeps going into the red at 122f

I am starting to wonder if maybe the power supply is robbing air from the cpu hs. I have no clue what to do, any suggestions?
PIC are available if needed!

 

ehm... so when you're gaming your cpu temp runs up to 50degrees C, but when decoding video it goes higher than that?

do you have intel active monitor?

can you post a screenshot of all temps and fan speeds when you are decoding video for say 1 hour?

 

If I knwe how to take a screen I would..lmao!
I am currently endcoding a dvd, temps are stable at 56c @cpu, 40c @ zone 1, and 48c @ zone 2.
The temps have gotten alot hotter than that while encoding, but here is something I found out today, with HT enabled, yes programs run faster, just a bit, but your cpu temps will be hotter also, so today before I started encoding a dvd, I disabled HT, and the temps have set at the above value for about 45 mins now, with the major difference being zone 2 staying at 48c, and not reaching 125-128f.
I am ordering a Thermal Take case tonight to see if that helps any, I am hoping that the aluminum in the case will lower my temps a bit, cause the case I have now, is steel. I will also be putting Artic Silver Paste on the cpu, and leaving the stock fan and heatsink in place, to test it out.

 

i wouldn't worry too much, your temps are fine.

my temps for decoding video:

cpu: 63
zone1: 47
zone2: 54

artic silver will lower ur temps, also the case probably lowers them a bit, but as long as both your zones stay under 55 c don't worry, cpu under 65 is ok i believe...

have a drink on me tonight as it took me a long time to get my temps down to these....

 

Well my computer never burns: i got my CPU up to 104C before by switching off my fans i could start to smell it burning so i turned um bk on

 

yes running an open case will allow airflow to your major components but i made a mistake one time of forgetting three very small but important pieces of equipment. northbridge , southbridge (if applicable), and memory. if you take the cover off of the side of your case and run it like that these three components are assured to get much hotter than if they were in a wind tunnel (so to speak)
thereby greatly reducing their lifespan and speed. i oced my nb one time without the side of the case and had to get a new mobo.......still have the burn marks from where i touched the heatsink heh this is a reply to the last post on page 1