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I've tried several searches and it seems I can't find a straight answer to this question: What is the best design for airflow?

The room I'm running this in has ambient temps up to about 30 Celsius, around 25 when the a/c is on.

Idle system temps are CPU: 40, Vcore: 38, GPU: 50 with the a/c off (GPU runs at full clock because I have an extended display with different a resolution on a gtx560ti)

Load system temps are typically up to CPU: 67, Vcore: 52, GPU: 70 with the a/c off running games.

Now, I have here a mid tower case with six 120mm Corsair Air Series SP fans rated at up to 2300RPM. 1 rear, 2 top, 1 front, 1 side, and 1 for the heat sink. Currently I have the side as intake blowing across the GPU and the front as intake.

For the GPU, does it make sense to have a side fan doing that, blowing directly onto the side? Its a single fan GPU with an open design, so it blows hot air off the GPU in every direction. I just don't want contradiction where air is leaving the vent at the very top of the card and the side fan is blowing it back in.

Does it make sense to always have the top fans as exhaust because of the logic that hot air rises, or do I want to point them downward blowing across my Vcore and having the back as the only exhaust?

Also if I have a top fan blowing upward away from my RAM and the CPU fan blowing through the heat sink from the RAM side, would that perpendicular airflow be contradictive? Do I want more air passing through the heat sink or do I want more air leaving the case?

Also, the motherboard I have is an Asus Sabertooth P67 with the plastic thermal shroud thingy. At first I had a 50mm assist fan to circulate air underneath the shroud, but then I realized that fan is right above the GPU so its drawing in hot air. This bothered me so I disabled the assist fan but that made the overall temp 2 degrees warmer. So instead of putting the assist fan back in, I opted for taking the plastic shroud completely off and replaced the 50mm assist fan with one of the Corsair fans mounted on the side panel that basically serves the same purpose. Am I better off like this or should I put the shroud back on with the assist fan? I didn't see a noticeable change in temps though.
 

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Pull 3 of your 5.25" bay covers and install a 120mm intake flowing air toward CPU cooler fan.
install your HDD in floppy drive bay and remove HDD cage.
Remove unused PCI slot covers
Side and front in (3 fans)
Back and back top out (2 fans)
Check out the second link in my sig.
 

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GhostRavenstorm

Does it make sense to always have the top fans as exhaust because of the logic that hot air rises, or do I want to point them downward blowing across my Vcore and having the back as the only exhaust?

I use to think that but hot air expands in all directions
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Yes, hot air expands and rises.. if there are no other forces in motion.

But fans move air wherever we want it to go. Heating and cooling systems in buildings, vehicles, etc. pay no attention to "hot air rises." Neither do computers.

Fans in a case are what moves the air, not the heat.

"Hot air rises" will not move enough air to cool most computer systems. CPU and GPU generate far too much heat.
 

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the principle behind hot air raising matters more outside the case then inside. for example, if you have a system that is located in a semi enclosed area such as under a desk, hot air raising matters when you are deciding where to place intake fans. if you place the intake fan at the rear exhaust port, then the hot exhaust from the GPU will be sucked back into the case as intake.

if the computer is placed in an open area where the exhaust gas has sufficient volume of cool air to mix with then this is less of a problem. however most computer cases are place in a semi cramped area where there isn't enough room/airflow for the exhaust to mix with ambient air then a good portion of the heat is still trapped in the rear of the case and having a rear intake or even top intake is a bad idea depending on the size of the case and how much room there is between the back of the desk and bottom of the desktop.

essentially you want to avoid hot exhaust gas from contaminating the cool ambient temp of the intake by having maximum separation of the 2
 

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Quote:
Originally Posted by ladcrooks View Post

GhostRavenstorm

Does it make sense to always have the top fans as exhaust because of the logic that hot air rises, or do I want to point them downward blowing across my Vcore and having the back as the only exhaust?

I use to think that but hot air expands in all directions
thumb.gif
While technically hot air does rise your old premise is also sound. Air and fluid dynamics are very similar. When you cool water into a pan of hot water the hot water will sit on the top of the cool water if there is nothing creating a flow in the water. if the water is in motion the cool water will absorb the heat of the surrounding hot water quickly and reduce the overall water temperature, the same is true with air.

If you design a case for a pure upward air flow you will gain a small benefit from a natural rise in the heated air. if you run a pure passive design the heat will naturally exhaust from the top. However if you, like most cases, have a strong current of air in motion the air will move across the motion pattern in the direction you tell it.

My goal in air flow has been to always create as much positive air flow as I can. So front and top intake should be good. The other mention of adding another front intake is a good idea. Your temps do not seem that bad however so I am not sure you need much more air flow.

Concerning the side fan, my own experience has not been good with using them. Side intakes tend to create air eddys at the bottom of the case which traps some hot air. Side exhausts tend to fight with the air intake of the video card and pull front intake air away from other cooling areas. Will your case support a bottom intake?
 

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i agree as air can be fighting 1 flow with another hence i always use in from front out at the back - never failed me and i am not going to argue over a silly degree cooler here or there
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same - if using fans at bottom of case then use the air at top for pulling out or reversal might be worthwhile testing as you wouldn't be sucking air closet to the floor = more dust
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Quote:
Originally Posted by ladcrooks View Post

i
same - if using fans at bottom of case then use the air at top for pulling out or reversal might be worthwhile testing as you wouldn't be sucking air closet to the floor = more dust
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This is a great point hence you must have a good filter on the bottom fan. Also I tend to use very low speed fans for the bottom, the idea there is to give some more fresh air to the GPU area, you do not need a lot, a nice trickle of air makes a world of difference.
 

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The dust down low is not a problem if there is enough clearance to keep air movement slow to bottom fans. Most cases do not have adequate clearance for for bottom fans which means air has to move much faster to feed them.. and this pulls more dust in.. Easy way to deal with it is raise case up.. like on an open bottom caster base.
 

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i have my case sitting on a bit of mdf with 4 castors taken of a sofa
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