# Cooling and fans - optimal



## JVPE (Jun 22, 2019)

Hi need to get my desktop cooler than it is.

I fans on my cpu and GPU and in the PSU. I have one cooler on the side of the computer blowing air out. But it still doesnt get cool enough. I have the option to install a cooler on the backside of the case. But which way is best. Blowing the air in or out? I dont want the computer to suck too much dust and stuff in.


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## Bill_Bright (Dec 17, 2004)

> I have one cooler on the side of the computer blowing air out.


Side, front, and bottom fans should blow cool air in. Rear and top fans should exhaust heated air out.


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## JVPE (Jun 22, 2019)

Bill_Bright said:


> Side, front, and bottom fans should blow cool air in. Rear and top fans should exhaust heated air out.



I dont have the option on the upper side of the case. And im not buying a new. There are two places to mount them on the side, and one in the back. What would be best in this situation?


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## Bill_Bright (Dec 17, 2004)

> What would be best in this situation?


I explained it. 

Side, front and bottom fans blow cool air in. If you don't have top or bottom, don't worry about them.

Rear and top fans exhaust heated air out. If you don't have top fans, don't worry about them. 

As a start, you need to turn your side fan around.


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## JVPE (Jun 22, 2019)

Bill_Bright said:


> I explained it.
> 
> Side, front and bottom fans blow cool air in. If you don't have top or bottom, don't worry about them.
> 
> ...



Thanks mate. Sorry for being stupid. I will keep your answers in a note. A little annoying to have all that air sucked in, i have a cat that sheds hair this time of the year. Can you somehow install dustfilters if the case doesnt have any ?


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## JVPE (Jun 22, 2019)

Sorry i meant me. Not you


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## Bill_Bright (Dec 17, 2004)

> Thanks mate. Sorry for being stupid.


You're asking questions about something you are not familiar with. That's being smart, not stupid. 

Yes, you can add dust filters. But I would recommend a new case that already has filters and perhaps better fan options. There are many but I really like Fractal Design cases.


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## JVPE (Jun 22, 2019)

Bill_Bright said:


> You're asking questions about something you are not familiar with. That's being smart, not stupid.
> 
> Yes, you can add dust filters. But I would recommend a new case that already has filters and perhaps better fan options. There are many but I really like Fractal Design cases.



Sounds like it would be easier to start from scratch with a new case and overhaul the cooling situation completely. But for now i will do what i can with the one i have  Thanks for your answers


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## Bill_Bright (Dec 17, 2004)

To add dust filters, yes a new case likely would be easier. But for now, it would be simple to remove 4 screws, turn the side fan around and mount it again with the four screws. 

BTW, how are you monitoring your temps? For real-time monitoring, I use and recommend Core Temp.

It is important to keep the heat-trapping dust and pet hair/dander under control. Cat hair is particularly problematic (as opposed to most dog hair - hounds might be the exception) because cat hair tends to be more oily and sticks to the surfaces within - like heatsink cooling fins and fans. If left there for too long, you almost need a chisel to scrape it off.


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## JVPE (Jun 22, 2019)

Bill_Bright said:


> To add dust filters, yes a new case likely would be easier. But for now, it would be simple to remove 4 screws, turn the side fan around and mount it again with the four screws.
> 
> BTW, how are you monitoring your temps? For real-time monitoring, I use and recommend Core Temp.
> 
> It is important to keep the heat-trapping dust and pet hair/dander under control. Cat hair is particularly problematic (as opposed to most dog hair - hounds might be the exception) because cat hair tends to be more oily and sticks to the surfaces within - like heatsink cooling fins and fans. If left there for too long, you almost need a chisel to scrape it off.



I use Speccy. It has a real time graph and realtime for all cores as well as the average for all cores. But will check Core Temp. Cant really do anything about the cat. I like her and dont want to get rid of her because of a computer. But keeping cat hair out of the ventholes is almost a daily chore. Will turn the fan around, get som dustfilters and install another fan at the back (already got one laying around), but cant find the computer screws  If i cant find them, ill just buy a bag of new ones  Thanks again


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## Bill_Bright (Dec 17, 2004)

I know Speccy. It is good for monitoring temps. If you like it, no need to use CoreTemp too. 



> but cant find the computer screws  If i cant find them, ill just buy a bag of new ones


You might check a local computer shop. They probably have a few 100 of them laying around.


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## kendallt (Feb 21, 2007)

I normally use open cell foam to make filters for my computers, cut it for a snug fit and it will hold itself in place. 
Since you only have one intake fan, cut it so you can either use self adhesive velcro strips to fasten it, or use small magnets. Refrigerator types work well. 

My current case has a couple of 6" chrome air cleaners on it, one for each intake fan. 

With good air flowing in, the other openings aren't likely to get hair in them, on mine I have the exhausts covered because I live on a very dusty road and everything gets covered in dust. (and my dust hedge is taking forever to grow big enough)


Edit: Used the chrome filter housings because I had them.


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## Bill_Bright (Dec 17, 2004)

> I normally use open cell foam to make filters for my computers


Some are meant for padding and don't let air easily flow through - so be careful what you use. 

Most home improvement stores have inexpensive replacement air filters that are used in small window air conditioners. These can easily be cut-to-fit a computer case fan vent.


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## kendallt (Feb 21, 2007)

That's why I specified 'open cell'. Normally use thin sheets1/8th to 1/4 inch thick.
One advantage to using an automotive style filter is that there is a lot more surface area and they don't clog up very easily. If you use a 'flat' material as a filter, hair will mat up on it pretty quickly.


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## Bill_Bright (Dec 17, 2004)

> That's why I specified 'open cell'.


But as seen here, open cell foam is typically used for padding and insulation - not as air filters. I recently used a can of open cell foam insulation to seal a hole through the outer wall of my house when I replaced the back hose bib. It is designed to block any air flow (and bugs, etc.).


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## kendallt (Feb 21, 2007)

You're talking about spray foam, I'm referring to polyurethane foam as used here:

https://unifilter.com/ 

Think we're getting away from the subject here though.


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## Bill_Bright (Dec 17, 2004)

That's why I said in my first reply to you, "_Some are meant for padding and don't let air easily flow through - so be careful what you use._"

Note the words, "open" and "cell" or "open cell" are no where on that page you linked too. Nor does a site search show any filter for filter material on that site that can be used to filter a computer case. 

So again, if making your own filter, I am just saying make sure you use materials designed to let air flow through it. Alternatively, there are materials not designed as filters, that work fine as filters - like a panty hose.


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## Rich-M (May 2, 2007)

I think fan usage is a matter of personal opinion. I was always taught you have a front fan blowing in and a rear fan blowing out and top and side fans interfere with flow of any of that. Especially side fan if blowing out can interfere with cpu fan blowing in to cool cpu so I recommend no side or top fans IMHO.


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## Bill_Bright (Dec 17, 2004)

> so I recommend no side or top fans IMHO.


A top fan exhausting heated air out can help, but if your computer is on or near the floor by your side, a top fan might be heard - and I hate fan noise. I mean I _really_ hate fan noise. :nono:

In my experience with side fans (which, if used, should always be intakes) is they often do more harm than good because they can disrupt the desired "flow" of cool air through the case by creating too much turbulence inside the case. The exception is when a side fan blows into a tube or conduit that channels the cool air directly onto the CPU or GPU cooler. 

But, because a side fan is mounted on a big side panel, the vibration from the fan motor (especially with cheap or worn fan bearings) can really cause a bunch of reverberating fan noise. Did I mention I hate fan noise?

That said, generally I'm with Rich here and prefer front fans drawing cool air in, and rear fans exhausting heated air out - with the front fans being behind removable, washable air filters.


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## Pursya (Feb 27, 2008)

For filter material try air conditioner filter.
https://www.airconfilters.com.au/products/washable-air-filters-media-material


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## kendallt (Feb 21, 2007)

I always go by which way my CPU fan is aimed. 
On mine the CPU fan points towards the front of the tower, so my exhaust fan is at the front. My intake fans are on the side, but one is positioned to 'feed' the cpu cooler and the power supply, the other is positioned to feed the GPU intake. 

Recently picked up a new case to replace the case I've been using for the last 20 years. (my computer is kinda like George Washington's axe)
It is set up a lot better for cooling, more vents and more locations for fans, just need to get the motivation to swap everything over. 

As for fan noise, the bigger the fan the more air it will move at lower speeds, so less noise. When run with a filter it is far less likely to collect dust and get off balance, so extremely unlike to start vibrating.


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## Melkesideck (Aug 19, 2008)

Have your case on the floor, (if you have carpet use a slab of wood to place it on) will help as heat rises


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## Zoandar (Aug 18, 2008)

If you have the type of case which has removable exterior panels, and the fans are mounted to an internal chassis, Swiffer dusting cloths make excellent intake filters. You can cut them to fit any shape, and tape them in place. They would be unseen from the exterior. Before I got into cases which now have filters, I used them extensively for years, and they worked very well. Just remember to change them out as needed depending on how quickly they get dirty.


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## Bill_Bright (Dec 17, 2004)

> When run with a filter it is far less likely to collect dust and get off balance, so extremely unlike to start vibrating.


Huh? Geesh! Are you letting a few pounds of dust collect in there before cleaning? I have never seen dust accumulate so much it causes vibration. I have seen neglected (for years! ) systems get so clogged no air can get through the vents and the fans slow down. But then when fans slow down, they are less likely to cause vibration. 

I don't know but if dust can cause a fan to vibrate, I would suspect it was a cheap fan to begin with since any dust would typically accumulate evenly and not upset the balance of the spinning blades. 

Anyway, I like windowed side panels. Not because I like to gaze in wonder at the internals of my computers. But so I can visually inspect for dust build up and spinning fans without opening the case. And my rule of thumb (if rising temps have not already triggered action) is when I see dust start to bridge the gaps between the heatsink fins, it is time to clean. And it should be noted, even if your case has good filters and your case fans are set for slight over-pressure to force intake air to come through the filters only, dust will still eventually build up inside the case, and internal case cleaning will still be required - just not near as often as an unfiltered case. 

Also, if me, I would turn your CPU fan around so it helps with the desired "front-to-back" flow of air through the case. I say this because your PSU fan exhausts out the back and that cannot be reversed. So "go with the flow"!


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## kendallt (Feb 21, 2007)

My present case has a top mount PSU and the CPU cooler is directly under it, so if I were to go with front to back air flow, I'd be fighting the flow off the CPU fan. 
With the way mine is set up, one intake fan feeds the CPU and PSU with cool external air, the other feeds the GPU, so what I have is side intake with front and rear exhaust.


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## Bill_Bright (Dec 17, 2004)

> My present case has a top mount PSU and the CPU cooler is directly under it


A very typical setup. 


> so if I were to go with front to back air flow, I'd be fighting the flow off the CPU fan.


That's why I said if me, I would turn the CPU fan around so it blows towards the rear. Your PSU fan is already pushing air out the back and you cannot change that. You have air coming and going from all directions. That creates turbulence that is not conducive to creating the desired "flow" of air through a case. 

There is nothing wrong with rear-to-front flow *IF* all the fans worked in harmony to achieve that. But since PSU fans (whether top or bottom mounted) always exhaust out the back, front-to-back is the desired objective. This is why with filtered cases, you never see the filters on the rear. 

At the very least, you should be monitoring your temps (I use and recommend Core Temp to monitor CPU temps in real time). And if your temps are staying on the high side, you should consider turning the CPU cooler and front case fan 180° around. 

This is an easy process but because it involves breaking the cured bond of the TIM (thermal interface material), you will have to thoroughly clean off all the old TIM and apply a fresh, thin as possible but thorough layer of new TIM when remounting the cooler. And be sure to unplug the computer from the wall and touch bare metal of the case interior BEFORE reaching in to discharge any static in your body. 


> so what I have is side intake with front and rear exhaust.


With more exhaust fans than intake, you create a "negative" pressure scenario. This is not desirable because it means more air is trying to get out through the fan vents than can come in. This causes a vacuum effect which results in air getting sucked in through every hole, crack and crevice - include through all your ports, optical drive, switches, etc. That is not good. 

You want slight over or "positive" pressure inside the case so the air pressure is constantly pushing out through all those holes, cracks and crevices preventing dust from getting in and clogging up those ports.


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## kendallt (Feb 21, 2007)

Other than the one in the PSU , I do not have exhaust fans, just the two intakes. The way my intakes are placed pushes cool air directly to them as well as flowing over my chip set coolers. The other feeds the video card. 
My CPU fan mounts on the side of the cooler with clips so it's simple to reverse the flow. 
Typically, a bottom mount PSU draws air from under the case through it's own filter on the bottom, so doesn't affect the airflow. (unless you mount it upside down) Those filters are normally the A/C filter style, one or more layers of fine mesh. 

The new case is a wider case with bottom mount PSU, picked it up because my old case, originally equipped with a p3 500 is getting a bit cramped.


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## Bill_Bright (Dec 17, 2004)

> I do not have exhaust fans, just the two intakes.


Huh?  You just said in your previous post, 


> what I have is side intake with front and rear exhaust.


If you have no fans helping with the exhaust by pulling heated air out, and if you are actively monitoring your temps and they are fine, then fine. If that works for you then it works for you. 

Regardless - I am just telling you the typical desired setup and that is to have a front-to-back "flow" of air through the case commonly achieved by an intake in front and an exhaust in back. Your method is not creating a flow and that would give me concern. 

And yes, I know how bottom mount PSU ventilation works and while most of the air is pulled through a bottom vent, not all is because bottom mount PSUs do not mount flush to the bottom of the case creating a seal between the PSU and case. They can't because PSUs have wire fan covers. So some air is pulled into the PSU from inside the case.


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