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Best air flow for a case

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March 9, 2010 11:13:21 AM

First off, my system is as follows:

AMD Phenom II X3 720 Black Edition with 4th core unlocked, not over clocked, stock AMD cooler
Gigabyte S-series motherboard, GA-MA78LM-S2H mATX
4gb Gaming Series DDR2-800 memory
ATI Radeon HD3870 w/512mb GDDR4 RAM
Hauppauge WinTV-HVR-1600 Analog/Digital combo tuner
3 SATA hard drives
1 SATA CD/DVD Reader/Writer
1 3.5 Floppy Drive
650 watt power supply

I have a mid-tower case and currently, my idle temps are around 50C and my full load temps have gotten as high as 68C which is getting too close for comfort. I do know that if I run Prime95, it will push the CPU temp to the shutdown point when it reaches over 70C. I haven't tried this running only 3 cores to see if the 4th core is actually causing the overheating.

My case is set up as follows:

Bottom front - 80mm case fan pulling air in
Top rear - PSU has two fans. One faces down into the case to pull air up. The other fan is at the rear to pull the air out.

I'm thinking of getting a new heat sink/fan combo, but I'm also thinking of putting in a 50mm fan in the back of the case. It's not at the bottom of the case. It's actually half-way up the height of the case. However, would this be enough to create proper airflow through the case, especially since I'm using an 80mm fan at the front or would the 50mm be too weak?

Thanks!

More about : air flow case

a b ) Power supply
March 9, 2010 11:25:20 AM

Hi. What is your budget for this upgrades?
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March 9, 2010 12:02:52 PM

I really can't afford to upgrade my case at this time after having just splurged on upgrading to the Phenom II (motherboard, memory and CPU).

What I'm hoping is, adding the extra fan in the back will help with the airflow as well as trying to clean up the cables in the front. I only have 1 ribbon cable for the floppy drive. Also, possibly getting a new heat sink/fan combo rather than the stock combo that came with the CPU.

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a b ) Power supply
March 9, 2010 12:22:18 PM

Ok, exist some basic principles on the airflow of a case, for example 2x120mm intake fan is the same that 1x240mm exhaust fan.

So, in your case you need a 80mm fan in the back side of the case for a proper airflow.
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March 9, 2010 12:27:26 PM

saint19 said:
Ok, exist some basic principles on the airflow of a case, for example 2x120mm intake fan is the same that 1x240mm exhaust fan.

So, in your case you need a 80mm fan in the back side of the case for a proper airflow.


Bummer. The back plate over there only can fit a 50mm exhaust fan. I supposed I could make my own exhaust port for an 80mm fan then. Here's a picture of an Antec case that is similar to what I have:



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a b ) Power supply
March 9, 2010 12:34:09 PM

Are you up to case mod work - cutting holes, etc? One thing you might consider is, when you get your new CPU cooling system, cut a hole in the side panel of the case the same size as the CPU cooler and lined up with it. I guess I am assuming the cooler fan draws air from above the CPU and blows it down over the heatsink, not sideways across the CPU. Then mount a protective grille over the hole, and I much prefer that you arrange a foam sheet dust filter on it, too. If you do that you get two benefits. One is that the CPU fan becomes in part a fresh air intake source. The other is that the CPU cooling air is outside cool air, not inside case pre-warmed air. To enhance this, try to fashion a sort of tube or collar mounted on the inside of the panel over that new hole so that it extends almost to the CPU fan. This will help ensure that the CPU fan's main air source is the hole, not case air.

I think you need larger fans if you can. However, it sounds like your case has little space for this. Do as much as you can. Basically right now you have one 80 mm intake fan on the front and one exhaust fan at the back (in the PSU), and you're planning on adding a very small additional exhaust fan. That's not a lot of air flow through the case, so I'm not surprised at your temperatures. Now that I see your photo, you might be able to add a second fan on the back in the space below where the first one goes. Maybe, to maximize the fans' effect, you could cut out all that hole-punched sheet metal over the fan exhaust faces and mount instead on the outside simple wire grilles with less airflow resistance.
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a b ) Power supply
March 9, 2010 12:34:59 PM

A 50 mm fan will barely be worth installing at the most you will get is 20 cfm hardly enough to make an impact on your temps. You should look into getting a better cae in the future.

How are your temps if you leave the side panel off?
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March 9, 2010 12:48:58 PM

Temps stay around 55C to 60C full load with the side panel off.

It's definitely an airflow problem.

Oh, and the picture was an example that is close to what I have, but it's not mine as I'm at work right now (yeah, typing on a forum at work) :pt1cable: 

I might be able to get an 80mm back there somehow. I'll have to look. I know I have one lying around somewhere.

The new heat sink I'm getting actually has the fan perpendicular to the CPU. Which way should the fan be facing? Towards the front or rear? I know this alone won't help with the air flow, so I'll still try to mount the 80mm fan on the back. I might have some room where there would normally be cards in the slots and could possibly use the slot holes as my grill.
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a c 144 ) Power supply
March 9, 2010 12:50:18 PM

saint19 said:
Ok, exist some basic principles on the airflow of a case, for example 2x120mm intake fan is the same that 1x240mm exhaust fan.

No. It's an area thing. Two 120 mm fans equals a 168 mm fan.

isamuelson, you are trying to use a case that should have been junked long ago. Modern cases have pretty much gone to 120 mm case fans as a minimum.

I think about all you can do, short of replacing your case, is to run with the side cover off.
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a c 144 ) Power supply
March 9, 2010 12:52:11 PM

saint19 said:
Ok, exist some basic principles on the airflow of a case, for example 2x120mm intake fan is the same that 1x240mm exhaust fan.

So, in your case you need a 80mm fan in the back side of the case for a proper airflow.

No. It's an area thing. Two 120 mm fans is the equivalent of one 168 mm fan.


isamuelson, you are trying to use a case that should have been junked long ago. Modern cases have pretty much gone to 120 mm case fans as a minimum.

I think about all you can do, short of replacing your case, is to run with the side cover off.
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a b ) Power supply
March 9, 2010 12:59:51 PM

isamuelson said:
Temps stay around 55C to 60C full load with the side panel off.

It's definitely an airflow problem.

Oh, and the picture was an example that is close to what I have, but it's not mine as I'm at work right now (yeah, typing on a forum at work) :pt1cable: 

I might be able to get an 80mm back there somehow. I'll have to look. I know I have one lying around somewhere.

The new heat sink I'm getting actually has the fan perpendicular to the CPU. Which way should the fan be facing? Towards the front or rear? I know this alone won't help with the air flow, so I'll still try to mount the 80mm fan on the back. I might have some room where there would normally be cards in the slots and could possibly use the slot holes as my grill.



You will want you CPUs heatsink blowing the air towards the back of your case make sure you figure out which way fan blows before installing some fans blow threw the heatsing and some suck air threw so you will have to figure out which it does.
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March 9, 2010 1:10:50 PM

saaiello said:
You will want you CPUs heatsink blowing the air towards the back of your case make sure you figure out which way fan blows before installing some fans blow threw the heatsing and some suck air threw so you will have to figure out which it does.


I purchased the Cooler Master Hyper 212 Plus Universal CPU Cooler (got a good deal on it):

http://www.coolermaster.com/product.php?product_id=6603

A picture on their website has it set up with the fan pointing to the front, so I'm assuming it must be pulling the air over the heatsink?


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a c 144 ) Power supply
March 9, 2010 1:27:47 PM

No. (Damn, I'm being contrary today. :)  )

It will be blowing air through the heatsink toward the rear exhaust fan.

Basic rule of case airflow is:
Intake - front and side.
Exhaust - rear and top.
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March 9, 2010 1:32:08 PM

jsc said:
No. (Damn, I'm being contrary today. :)  )

It will be blowing air through the heatsink toward the rear exhaust fan.

Basic rule of case airflow is:
Intake - front and side.
Exhaust - rear and top.


Isn't that what I said with the picture? ;) 

So, the way they have it set up in the picture is the correct way to install it, then?

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March 9, 2010 1:44:57 PM

Best answer selected by isamuelson.
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a b ) Power supply
March 9, 2010 2:02:02 PM

isamuelson said:
Isn't that what I said with the picture? ;) 

So, the way they have it set up in the picture is the correct way to install it, then?


Yes that is the right way to set it up.
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March 9, 2010 2:05:16 PM

saaiello said:
Yes that is the right way to set it up.


Thanks! I don't know how much this will help, but I'm hoping if I can jury-rig an 80mm fan on the back along with this cooler that I can keep the temps in the mid to low 60's.

I'll have to definitely look into getting a case upgrade soon, though. It's just a matter of getting approval from the wife! [:isamuelson]
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a b ) Power supply
March 9, 2010 10:04:29 PM

If you have to assemble the CPU heatsink and fan, watch for arrows on the fan outer case. There often are two. One is direction of fan blade turning. The other is direction of air flow. Air flow direction tells you which way to mount the fan to the heatsink for blowing or sucking.
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March 11, 2010 4:28:31 PM

Well, after about 2 hours of working on this, I finally got the heat sink installed. Now, it didn't take me 2 hours to do the heat sink. That took about 15 minutes, but I still had to remove all my cards and connections because I had to remove the current heat sink base and install a completely new one for the Hyper 212+ heat sink.

The rest of the time was spent replacing ribbon cables with round cables and rerouting my wiring so that I had most of it moved out of the way and tucked behind the rear side panel.

Since having installed it, plus a rear fan, my idle temps have gone down to around 40C. Top load while playing games hovers around 46/47C. Running Prime95, through 5 tests, my CPU temp never climbed above 52C! I'm sure the heat sink has a lot to do with it, but I also feel that having moved wires out of the way and installing the fan in the back has had a positive effect as well.
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October 12, 2010 8:23:36 PM

Hi can you ps tell me if it was easy to install your 212 plus cooler? I have purchased same one and have been told you need to be a Octopus to do it! Thanks
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