Intake fan to outake fan ratio

shadowscotland said:
My 2p worth

after 20sec the case reaches equalibrium: (numbers are unitless)
10 in + 8 out + 2 losses (via holes) = 10 'flow' (high pressure case)
10 out + 8 in + 2 gains (via Holes) = 10 'flow' + dust (low pressure case)
The 'flow' is the same, negative pressure has more dust :p .

[slightly OT]
Air flow routes are more critical:
A direct 'flow' of 8 will have same cooling potential that a turbulent 'flow'' of 12.

.5 (distance) x 100 (temp gained) / 10 (flow) = +5 Case temp (baseline)
To reduce temps, reduce one or more of the three factors.

Less distance for air to travel (more planning/better case)
.4 x 100 / 10 = 4
Use a cooler chip (AMD / C2D)
.5 x 80 / 10 = 4
More air flow (Bigger/faster fan)
.5 x 10 / 12.5 = 4

Back to my example above to acheive base line temp.
.4 x 100 / 8 = 5 (A direct flow of 8)
.6 x 100 / 12 = 5 (turbulent flow of 12)

Practical usage:
So you've oc'ed your chip, 50% more heat .5 x 150 / 10 = 7.5 (to hot)
You have various options.
.5 x 150 / 15 = 5 (an extra 50% more air flow)
.4 x 150 / 12 = 5 (an extra 20% more air flow well routed)
.4 x 125 / 10 = 5 (Improved cooler plus well routed flow)
.01 x 150 / .5 = 3 (liquid cooling direct on heat source, water flow 1/20 of air) :D
[/slightly OT]
Click to expand...

Strewth I'm sober and I don't get that at all! :p
Seriously though folks, like said earlier, trial and error is the best bet. I personally prefer more pulling out with negative internal pressure. From what I've seen the difference is minimal anyways. I do think its agreed that a coupla 120mm fans are gonna be better than a coupla 80mm fans though, more air and quieter running.
 
In my opinion positive pressure (ie more air being forced into the case than being sucked out) is the way forward, especially if you are aiming for a quiet PC. The amount of negative pressure one can create in a case with only 1 or 2 120mm fans acting as exhausts is minimal, and as other posters have said, it does make for a more dusty case.

With a positive pressure system it is also much easier to create the airflow you desire, as with a negative pressure system air will simply follow the path of least resistance, be it through gaps between PCI cards or open screw holes.

My setup is an Antec SOLO with the PSU ducted from the front 5.25" bays so it has an independent supply of cool air. I have 2 92mm fans at 5V at the front of the case and air is extracted from within the case by the cooler on my x1950xtx and the 120mm Antec Tri Cool fan on its lowest setting. All wire grills have been snipped off and their edges lined with rubber edging. Air only enters at the front of the case, which makes cleaning it much easier, as all that's needed it to remove the dust filter and rinse it.
 
advantage to active intake (ie more intake fans than exhaust) is that it gets where you want it to, so you can target hotspots easier.

Who NEEDS cool air being sucked in via the optical ports, and other cracks and crevasses when you can have less exhaust fans, and more fans pushing cool air towards you components that need it most!

of course, if you dont have filters.... you are pushing cool DUSTY air at components that need cooling. But passive intake does that anyway.
 
Well I now have it set up with the following:

120mm front intake
80mm side intake
120mm rear exhaust

So not counting the PSU there is greater intake than exhaust, that will have to do as there is nowhere left for me to increase the intake.
 
you could just get this case

cliolb9.jpg


and air flow is done (just add 2 more fans @ the back)

looks better in black tho
 
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http://image.******.com/UK/R0123912-01.jpg
http://image.******.com/UK/P0123912-01.jpg
i have the black one. a lot nicer will post good pics when i can take em
 
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That case is over kill - it's just for the asthectics. :rolleyes:

Ok previous post was a little heavy :o
but a little maths or logical thinking can save you hours with the T&E approach.

All I'm saying is more air = less heat but more sound and dust
BUT a more efficient air flow = less heat, sound and dust.

If you just want to get stuck in - Trial and error is by far the best way at maximising your cases cooling potential. If you have a window it's even easier as you can see the airflow with a little smoke (but don't go burning your house down).
If you've never done this sort of thing before start with the case manifactures website - it may tell you best airflow setup.
Next look at Lian Li website for inspiration - as they have animated thermal flow diagrams of all their cases.

Get a few of the largest fans your case can take and try out different flow combinations. in various locations. and test your temps with each. Dont forget your HS fan and PSU fan. And some times covering vents make a case more efficient/quieter.

Basic setups include.
In bottom, out top
In front out back (generally a good place to start)
in bottom front, out top back
in bottom front and side, out back
In sides out back (HTPC)
In top out back (HTPC)
zoned case with their own dedicated in/out
'Windtunnel' approach (all fan pointing in same direction inc GPU/HSF/PSU)
etc, etc, etc

Once your happy that you've acheived best temps - reduce volts or get better fans to minimise noise (if that important to you)
 
What about the antec 900?

im impressed by the 200mm exhaust fan on the top (as well as the other fans)but from what u r saying (about more in than out) would it be better to turn the fans around and swap airflow from the back to front ie more cool in and warm exhausts at the front "inputs".

is it possible to emove/turn the fans in this case!?

Thanks
 
Dan2kx said:
What about the antec 900?
Click to expand...

It's been tested with it's default flow direction - I'd leave it as is. As many OcUK reviews will testify its a excerlent out of the box proformance case. Just spend some time to keep you wires tidy and hoover once a month.
 
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