Best fan configuration?

C

Cyber-Garfield

Limp Gawd
Joined
Sep 24, 2001
Messages
372
Ok, got a new case with spots for 5- 80mm fans (1 front, 3 side, & 1 top) and 1- 120 mm in the back. I have the back 120mm fan in and 2- 80mm fans that will go in. Was thinking of getting 3 more 80mm fans to go in the case and fill all the spots. Is it the best configuration with front and side blowing in, and top and back blowing out?
 
Um... I'd have all the front ones pulling in, the rear 120 pushing out...

The side of the case should be blowing out if it's over the CPU (most are) or blowing in if it's over the GPU. This is, of course, if you're using the stock HSF.

The top should be exhausting air.
 
well lets throw more options in here... i would use the back and top as exhaust and the others as intake
 
Back and top should be exhaust, front and side should be intake. Try to keep the airflow positive (more air blowing in than out) since it helps expel dust.
 
Try to keep the airflow positive (more air blowing in than out) since it helps expel dust.
Click to expand...

old bad myth and was mainily based on the assumption you dont want air sucked in thru the floppy and CD slots and dust building up in the drives. (overpressure the case so air blow out the cracks )

Just think about it, more in that out ? How the heck is that susposed to keep dust out ? Well if you had micron sized filters on all our fans it might help some. You would probally do as well to change the furnace filters on a monthly basis. Most disregard the dust buildup in the drives as not an issue with modern drives but I wont say it doenst happen.

For best cooling you want good air flow, which means FLOW, balance CFM from in to out (about as much cfm in as out ) and when in doublt more out dont hurt and helps suck air in the intakes, if you overpressue the case the intake fans dont work well, look up static pressure as it relates to fan airflow curves.

So you get a choice proper airflow and good cooling and once a year blow the dust out of your floppy or crappy cooling and perhaps the reduction of dust buildup.




Per standard fee schedule, my advice/opinions are worth exactlly what you paid for them.
 
If I had
1x120mm intake
1x120mm side (over GPU) intake
1x120mm intake on the rear of the case blowing air onto the cpu/heatsink---maybe change this to an exhaust.
Scythe infinity/ninja with a 120mm fan on it
and
2x120mm exhaust on the top of the case

do you think this would work pretty good on a Lian Li g70?
 
BillParrish said:
old bad myth and was mainily based on the assumption you dont want air sucked in thru the floppy and CD slots and dust building up in the drives. (overpressure the case so air blow out the cracks )

Just think about it, more in that out ? How the heck is that susposed to keep dust out ? Well if you had micron sized filters on all our fans it might help some. You would probally do as well to change the furnace filters on a monthly basis. Most disregard the dust buildup in the drives as not an issue with modern drives but I wont say it doenst happen.

For best cooling you want good air flow, which means FLOW, balance CFM from in to out (about as much cfm in as out ) and when in doublt more out dont hurt and helps suck air in the intakes, if you overpressue the case the intake fans dont work well, look up static pressure as it relates to fan airflow curves.

So you get a choice proper airflow and good cooling and once a year blow the dust out of your floppy or crappy cooling and perhaps the reduction of dust buildup. .
Click to expand...

No... more intake gives your case positive pressure, and keeps dust out. This isn't a myth - there's far, far more holes in your case than where fans are positioned. With negative case pressure, air will be sucked through these holes and over time the dust will build up along every small crack or opening. With positive air pressure, small amounts of air will be pushed out these holes and thus dust will never build up. This means the only places where air is going in is your intake fans, which can easily be fitted with a filter.

Along the lines of your logic, more intake would "help push air through the exhaust". In all honesty, the only in/out fan that's of importance with this consideration is the PSU, which is exhaust, thus negative case pressure would overwork the PSU fans.

In terms of flow, I've found it's not so much about pressure (although I will strongly suggest having some positive pressure, if any) but rather the layout of your fans and wiring. If you have wire spaghetti in your air flow, it's going to be terrible, so clean up your wiring. Fan positioning should follow the natural movement of warm air... low to high. Consider the front fans are low and are cold, so they should be intake. As the air moves across components, it warms up, so the top and back fans should be exhaust. Side fans should be setup to best compliment your air pressure or any possible ducts you'd like... if you have a CPU fan that's designed to blow down onto the heatsink, then set the sides to intake and duct to the CPU. Same goes for anything else, don't just assume a given component needs one way or another like someone else suggested.

Pressure-wise, you'll have to research your fans and figure out your total CFM, then divide in half and try to make an arrangment based on size and CFM for the pressure you want.
 
sumofatguy said:
well lets throw more options in here... i would use the back and top as exhaust and the others as intake
Click to expand...
yes - this is how most of the cases are designed to flow.
 
No...
Click to expand...


Nope dont buy it. and I am happy to have some dust in the cracks it helps seal em up :eek: as far as there being more area in cracks than a fan opening, hmm what kind of case do you have ? Mine is not that way. now there are some slots/vents at the bottom of the side pane, designed for air to be sucked in the bottom to help cool lower cards, overpressure would have air blowing out those vents. Dont think thats a good idea. Anyway in the end we both advocate a close to balanced solution and I tend to favor underpressuing the case, you tend to overpressue, with good airflow it wont matter that much.

probally will see more benifit from removing/opening up the fan grills than either under or over pressuing the case :)
 
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