Question Whats a good intake/outtake ratio

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BeastHotDogGUY

BeastHotDogGUY

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Apr 13, 2023
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so im gonna get the h710i, kraken z73 in front, 3x f120 fans on top, and one f140 in back but was wondering how many i should put for exhaust and how many for intake?
specs:
cpu: 5 5600g
gpu: 1660 super
ram: 8gb 3200mhz
psu: cooler master 600w 80+ gold

and I dont want to upgrade parts rn
im going to do a vertical mount gpu btw
 
You generally want to follow the "front intake, top/rear exhaust" rule of thumb. You could just do the 3 rad fans as intake and the single rear 140mm exhaust for your hardware. No need for the top fans.

IF you want to use all the fans you're stating, consider the rad in the top as exhaust, 140mm rear exhaust, and the 3 F120 fans in the front as intake.

360mm rad for a 5600G, haha.
 
tennis2 said:
You generally want to follow the "front intake, top/rear exhaust" rule of thumb. You could just do the 3 rad fans as intake and the single rear 140mm exhaust for your hardware. No need for the top fans.

360mm rad for a 5600G, haha.
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im gonna upgrade the cpu soon and i want the fans on the top so should i just do two intake on top and 1 exhaust on top?
 
Note that if you have only fans on the top part of the case in all exhaust, don't put any in front of the CPU cooler. All those are doing is sucking up intake air before the CPU cooler has a chance to get to it. If you have a CPU AIO cooler and you put the radiator there, that's a different story.

In any case, there's no "good ratio" per se. Just play around with different configurations and see what gives you the best cooling for the noise you're willing to tolerate.
 
In/out is still a thing of personal preference, there is single perfect radio.

The old idea was
more in = air gets blown out through all the little gaps, less dist, but less cooling.
more out = air gets sucked in through the gaps, better cooling, but it also sucks in dust.
And more fans means you can have more airflow at the same rpm or same airflow at less rpm (and noise)
 
hotaru.hino raises an important point above. To be clearer, when you have TOP exhaust fans in three positions as well as FRONT intake fans all the way from top to bottom, you get a short-circuit of air flow at the top front. The air coming in the top front gets blown right out of the top by that fan nearest the front. You can avoid this by NOT placing a TOP fan in the FRONT location.

So, you will have a 3-fan rad in the front panel as INTAKE of room air. You will have one exhaust fan at the rear. I recommend that be a 120 mm size, not 140, to help with air balance. At the TOP, install TWO 120 mm fans as exhaust, in the rear and middle positions, and none at the front. This gives you three air intakes at front (but with slightly reduced air flow due to resistance by the finned radiator), and three 120 mm exhaust fans to balance them. It avoids the "air flow short circuit" at top front.

That arrangement may not give what I consider the "ideal" air flow balance of small positive pressure. The three rad fans' air flow is reduced a bit. You can deal with this later because the three exhaust fans are controlled by different headers from the intake fans. The front rad fans (intakes) should be controlled by the CPU_FAN header. So you can set the configuration of the header(s) for the top and rear fans to use a custom "fan curve" that has them run slower than the default curve, thus reducing their combined exhaust flow capacity to slightly less that what the rad fans are bringing in.
 
Hotaru.hino's comment about 3 top fans was more applicable for a tower-style CPU cooler.

In this case where the 360mm AIO is the case intake, the air coming in from there is pre-heated by the CPU wattage. Good to suck that up and out the top as quickly as possible. The AIO doesn't care whether its exhaust is existing the case further back or not, it's already done it's job. At this point, you're just trying to make sure hot air doesn't stagnate below the GPU.
 
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Paperdoc said:
hotaru.hino raises an important point above. To be clearer, when you have TOP exhaust fans in three positions as well as FRONT intake fans all the way from top to bottom, you get a short-circuit of air flow at the top front. The air coming in the top front gets blown right out of the top by that fan nearest the front. You can avoid this by NOT placing a TOP fan in the FRONT location.
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he does have rad at front, so that intake wont be exactly cold intake
 
The point that using a rad and fans as the case front INTAKE air source means that the case's air supply is now pre-warmed, is part of the debate over whether to do this ever. Consider the MAGNITUDE of this effect. In most AIO systems the air pre-warming amounts to a very few degrees (1 to 3 or 4?) of the air supply used to cool the case interior. This air is NOT hot! The practical impact of that is simply that the automatic control system of the CASE VENTILATION FANS will have those fans run slightly faster to ensure that the case components' temperature (as measured by the temp sensor on the mobo) is kept to the SAME temperature as if the intake air were cooler. Unless your case vent system is badly undersized so that it normally operates at max cooling capacity even at moderate workloads, this is NOT an issue.

Another way to look at that: Doing it this way is the same as NOT doing it, but working on a warmer summer day, when your ROOM temperature is a couple degrees warmer than in winter. Would you panic over that?
 
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Paperdoc said:
The practical impact of that is simply that the automatic control system of the CASE VENTILATION FANS will have those fans run slightly faster to ensure that the case components' temperature (as measured by the temp sensor on the mobo) is kept to the SAME temperature as if the intake air were cooler.
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Typically the default temp to adjust case fans is the CPU temp, so if you want this^ to take place, you'll need to set a different temp sensor (if possible).

Ultimately front/top rad is choosing whether you want your CPU or GPU to be cooler [compared to the other orientation].
Rad in front = CPU is getting the coolest air, dumping waste heat into the case for the GPU to inhale. Unless there are intake fans mounted in the bottom (or the bottom front fan isn't blowing through the rad) there's no other source of "fresh air" coming into the case unless you have negative air pressure.
Rad in top = CPU is sucking up [some of]* the GPU waste heat from inside the case. Proximity from rad to top front fan(s) can lessen this effect, but the CPU won't be as cool as if the rad was located on the front panel.

As to which orientation, really depends on the CPU and GPU wattage comparably and the cooler on each. If the GPU cooler is weak, prioritize cooler air for the GPU, likewise vise versa. In this case of a 360mm rad on (ANY) AMD CPU, I'd probably mount the rad as top exhaust. It's not going to have any problem cooling the CPU, and that way you get tons of "fresh" and unrestricted (rads introduce pressure obstruction, lowering CFM) air coming into the case to keep the GPU cooler.
 
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tennis2 said. "Typically the default temp to adjust case fans is the CPU temp, so if you want this^ to take place, you'll need to set a different temp sensor (if possible)."

Often that's true, but not always. To me it makes NO sense that the DEFAULT setting on a CHA_FAN or SYS_FAN header may be to use the CPU chip's internal temperature sensor. A fan for CASE VENTILATION should ALWAYS use a temperature sensor on the mobo to guide it, because its major focus is on removing heat from mobo components.

When an AIO system is used as the major INTAKE source of air in a case, of course that set of rad fans will be tied to the CPU temperture - that IS what those fans are cooling. A similar situation when the rad is in an EXHAUST position. For those set-ups most control of mobo component cooling is done solely by whatever other fans are in use connected to SYS_FAN or CHA_FAN headers, and certainly those should be controlled according to a temp sensor on the mobo. That cooling system just has to make do with the air supply it has, even if it cannot change that to meet mobo needs. Such systems certainly CAN operate well that way.
 
1:1
The intake volume will always be equal to the exhaust volume.

Seems like mixed priorities to spend twice as much on cooling as you do on the processor itself.
Why not try the stock cooler and see how you do first.
If you have a heat issue, then look at fixing it.

Perhaps I missed it.
What is the make/model of the case?
 
Paperdoc said:
Often that's true, but not always. To me it makes NO sense that the DEFAULT setting on a CHA_FAN or SYS_FAN header may be to use the CPU chip's internal temperature sensor. A fan for CASE VENTILATION should ALWAYS use a temperature sensor on the mobo to guide it, because its major focus is on removing heat from mobo components.
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I don't set the defaults. Just wanted to make OP aware that it's probably going to be CPU temp as the default temp sensor source for all fan headers.

On my AsRock B550 Phantom Gaming ITX, the default for all fan headers is CPU temp, or I can change it to MB temp (assuming this is the highest of any/all mobo temp sensors).
 
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