Looking for input on fan placement for my Define R5

[azrael]

So I'm *finally* ready to build/upgrade my current PC during my Easter vacation. I'd like to get some input on how I envision the fan placement. Case is the Fractal Design Define R5. Fans available are 2x Fractal Design Dynamic GP-14, 2x Arctic P14 PWM CO and 2x Corsair LX140. All fans are 140 mm ones.

Originally, I wanted to use the P14s as intake fans, but I've now bought the 2-fan LX140 starter pack because of their static pressure. Seems like static pressure is more import than airflow in my case scenario. These fans will be mounted the "red" position.

This leaves the GP-14s and the P14s. Right now, I'm thinking of putting one P14 at the "yellow" position as an extra intake fan and the other P14 at the "green" position as exhaust fan. Alternatively, the GP-14s at the same positions.

Am I bonkers? (rhetorical question btw, as I most assuredly am )

 

[Chrispy_]

Air cooler on the CPU, right?

Red and yellow zone for intakes will be useless unless you remove the venting at the top of the case. You want as close to balanced airflow between intake and exhaust as possible, but ideally slightly positive pressure so that the only dust getting in does so via the intake filters.

The filtered intakes will want the most static pressure, so red zone should be the LX140
Yellow intake should be static pressure if it's filtered, regular airflow if it's unfiltered and the perforations in the bottom of the case allow for decent breathing.
The exhausts can be whatever's quietest. I would probably add one top fan at the rear and leave the forward top bay covered.

3x intake + 2x exhaust should work well if your GPU doesn't dump a ton of air directly into the CPU cooler's intake. If it does, there's no ideal solution to that, but I've made a duct to sit on the blow-through end of a GPU before to ensure that its hot air is directed around to the side of the CPU cooler, not directly at the CPU cooler's fan.

 

[Kwadratowicz]

What parts are You going to mount in this rig?

Specs from manufacturers

Fractal Design Dynamic GP-14= 68.4 CFM
static pressure max (i guess) =0.71 mm H2O

Arctic P14 PWM CO =72.80 cfm
static pressure max(i guess) =2.40 mmH2O

Corsair LX140 =84.7 CFM (is it rgb?)
static pressure max =4.86 mm-H20

 

[thestryker6]

It depends on the hardware you're putting in the system. I have one of these cases that I use for a server box and I have 2x P14 in the front, one in the back and one on top with a Peerless Assassin 120 cooler. My CPU is the only high power consumption part in that system so I don't particularly need more airflow.

The bottom intake isn't all that good unless you have the case raised up as there isn't really enough room just from the feet for good intake. You wouldn't need to raise it up a lot, maybe an inch, for it to be more effective.

 

[azrael]

Sorry, forgot about the other components.

CPU cooler will be a ThermalRight Peerless Assassin 120 SE.
CPU a Ryzen 7 7700 (for now).
Graphics card an ASUS ProArt RTX4080.
2x 48GB DDR5 memory modules.
Storage will be all the disks in my current system, but the 970 EVO (system drive) will be replaced with a 990 Pro.

I'm looking for as much positive pressure as possible. Would rather not utilize a top exhaust, but is doable if necessary. Oh, and the middle drive bay will be removed.

 

[FreedomEclipse]

Since your case has the door at the front. I would recommend a fan with good static pressure like the Arctic P14 Max. Its pretty cheap and cheerful

Otherwise any fan from this chart will do you solid

Crmaris is also very well known around TPU (we all miss him )

As you can see the P14 Max is a pretty good middle ground.

 

[thestryker6]

With a card that can dump that much heat and an air cooler you definitely are going to need two exhaust fans (one in back and one top back). I think raising up the case further so you can utilize the bottom intake better would be a good idea too.

 

[Chrispy_]

I'm looking for as much positive pressure as possible.

Why? It doesn't improve cooling. More airflow improves cooling and lets you run the fans slower and quieter.

I graduated as an engineer, I've done a lot of work on fluid dynamics and worked for Rolls Royce on their jet turbine blades. "Positive pressure" in a PC case is damn-near meaningless because we're talking about miniscule, almost negligible changes of 1-2% at most. Any attempt to create meaningful positive pressure that increases air density would require you to use silicone sealant around every case panel and vent, then replace the exhaust fans with pressure valves. Even then, more air density makes very little difference to thermal transfer capacity, it's only of relevance if you're trying to burn something and need more oxygen (eg, internal combustion engine). So in a hypothetical situation where you had a very high-pressure case, it still wouldn't help with cooling in a measurable way!

Realistically, when people talk about "positive pressure" for a PC case, it's about ensuring that the tiny (almost negligible) imbalance of pressure is internally positive so that a trickle of air pushes dust away from all the the gaps, crevices, and corners of their case, rather than sucking that crap deep into every impossible-to-clean corner of your case and making the inside of your PC resemble the dust bin of a vacuum cleaner.

For the best airflow-to-noise ratio, you want balanced airflow between all intakes and all exhausts. If you notice dust collecting on the panel gaps and seams then you have slightly negative pressure, so either speed up your intake fan curve slightly or slow down your exhaust fan curve slightly.

 

[azrael]

Since your case has the door at the front. I would recommend a fan with good static pressure like the Arctic P14 Max. Its pretty cheap and cheerful

Otherwise any fan from this chart will do you solid

View attachment 394405

Crmaris is also very well known around TPU (we all miss him )

As you can see the P14 Max is a pretty good middle ground.

That's why I went with the LX 140 after initially getting the P14s. The LX140s seem to be pretty much the best fans out there for static pressure. Very expensive, though.

With a card that can dump that much heat and an air cooler you definitely are going to need two exhaust fans (one in back and one top back). I think raising up the case further so you can utilize the bottom intake better would be a good idea too.

May have to consider that. Case will stand on my desk, btw.

Why? It doesn't improve cooling. More airflow improves cooling and lets you run the fans slower and quieter.

I graduated as an engineer, I've done a lot of work on fluid dynamics and worked for Rolls Royce on their jet turbine blades. "Positive pressure" in a PC case is damn-near meaningless because we're talking about minisclue, almost negligible changes of 1-2% at most. Any attempt to create meaningful positive pressure that increases air density would require you to use silicone sealant around every case panel and vent, then replace the exhaust fans with pressure valves. Even then, more air density makes very little difference to thermal transfer capacity, it's only of relevance if you're trying to burn something and need more oxygen (eg, internal combustion engine). So in a hypothetical situation where you had a very high-pressure case, it still wouldn't help with cooling in a measurable way!

Realistically, when people talk about "positive pressure" for a PC case, it's about ensuring that the tiny (almost negligible) imbalance of pressure is internally positive so that a trickle of air pushes dust away from all the the gaps, crevices, and corners of their case, rather than sucking that crap deep into every impossible-to-clean corner of your case and making the inside of your PC resemble the dust bin of a vacuum cleaner.

For the best airflow-to-noise ratio, you want balanced airflow between all intakes and all exhausts. If you notice dust collecting on the panel gaps and seams then you have slightly negative pressure, so either speed up your intake fan curve slightly or slow down your exhaust fan curve slightly.

I was of the impression that airflow fans only really help with no or minimal obstruction inside the case. At least that's what I've read scouring the interwebs for information. Considering I have a closed case, there will be quite a lot of obstruction.

 

[Chrispy_]

That's why I went with the LX 140 after initially getting the P14s. The LX140s seem to be pretty much the best fans out there for static pressure. Very expensive, though.

May have to consider that. Case will stand on my desk, btw.


I was of the impression that airflow fans only really help with no or minimal obstruction inside the case. At least that's what I've read scouring the interwebs for information. Considering I have a closed case, there will be quite a lot of obstruction.

airflow fans lack static pressure, and you don't need any static pressure for an exhaust fan - there should be empty space both in front and behind them unless you're doing something very wrong with component layout, or your exhausts are filtered (they shouldn't be!)

 

[azrael]

airflow fans lack static pressure, and you don't need any static pressure for an exhaust fan - there should be empty space both in front and behind them unless you're doing something very wrong with component layout, or your exhausts are filtered (they shouldn't be!)

That's why the LX140s go in the front and either a P14 or a GP-14 goes in the back. At least that's the plan, according to my initial post.

I guess, if possible (thickness), the P14s are preferable to the GP-14s?

 

[Chrispy_]

That's why the LX140s go in the front and either a P14 or a GP-14 goes in the back. At least that's the plan, according to my initial post.

I guess, if possible (thickness), the P14s are preferable to the GP-14s?

It doesn't really matter - whichever is quietest for any given flow rate.

I'm assuming noise levels matter to you, otherwise you wouldn't be concerned about fan placement and type, you'd just fill every fan bay and run them loud.

 

[azrael]

It doesn't really matter - whichever is quietest for any given flow rate.

I'm assuming noise levels matter to you, otherwise you wouldn't be concerned about fan placement and type, you'd just fill every fan bay and run them loud.

Indeed. Noise matters quite a bit to me. One of the reasons to go for a case with a door. even though I know that's far from optimal for cooling.

 

[Shrek]

I like 30mm depth fans if they fit.

 

[Chrispy_]

Indeed. Noise matters quite a bit to me. One of the reasons to go for a case with a door. even though I know that's far from optimal for cooling.

Quietest is definitely "more fans, run them slower".

If you can do three intakes, three exhausts, and keep the intakes running ever so slightly more airflow than the exhausts, that's your best cooling per decibel.

 

[Shrek]

That is the route I took, more fans run slow; hopefully this will also result in less dust.

 

[anonuser57]

Most possible static pressure at front intake is optimal for that case. The front is constrained and the bottom is also filtered so three intakes and one exhaust is sane.

 

[azrael]

Quietest is definitely "more fans, run them slower".

If you can do three intakes, three exhausts, and keep the intakes running ever so slightly more airflow than the exhausts, that's your best cooling per decibel.

Most possible static pressure at front intake is optimal for that case. The front is constrained and the bottom is also filtered so three intakes and one exhaust is sane.

I had hoped I could fit 3x 120mm LX120 fans in the front, but that's not possible. So I'm stuck with 2x 140 LX140 fans in the front and a possible third intake fan would then be, as originally mentioned, in the bottom of the case between the PSU and the bottom drive cage/bay.

Well, I'm happy I'm not completely off with what I had planned. All fans are already bought (although I could potentially return the LX 140s, but why; especially since they are 25 mm thick).

That is the route I took, more fans run slow; hopefully this will also result in less dust.

Although the R5 has plenty of dust filters, it lacks them for the upper 5.25" drive bays and the top (which is why I'm not so happy opening it up for exhaust due to dust).

 

[thestryker6]

Although the R5 has plenty of dust filters, it lacks them for the upper 5.25" drive bays and the top (which is why I'm not so happy opening it up for exhaust due to dust).

The top of mine has three separate panels so I only took out one of them. When using a 140mm exhaust fan there isn't a whole lot left open:

 

[Chrispy_]

That is the route I took, more fans run slow; hopefully this will also result in less dust.

Dust is, unfortunately, worse the lower your airlow is.

Dust sticks to stuff with a very weak electrostatic force, so slower airflow, slower spinning fans, and quieter systems will - on average - gather more dust than aggressive, high-rpm fans and cases with stronger airflow that can overcome the weak electrostatic forces binding dust particles to the insides of your PC.

Your best defence against dust is fine filtration on all intakes and a little bit of positive case pressure, but obviously the finer the filters are, the more hinderance to airflow there is. Quiet fans with high static pressure will help for filtered airflow, and if your case allows for it, creating some separation between the intake fan rotor and the filters also helps, but it's always a tradeoff between dust filtration and the efficiency of your cooling.

The top of mine has three separate panels so I only took out one of them. When using a 140mm exhaust fan there isn't a whole lot left open:

you won't get dust in there (highlighted area) when the fans are running, as the fan will entrain surrounding air, sucking it out of the case through those holes, similarly to bypass air in a turbojet engine or how those Dyson bladeless fans work.

 

[mb194dc]

I have 3 x Noctua NF-A14 in my Fractal R5, and a bottom fan from other brand with Argus fan control software to keep the RPM sane, always useful to have 3000rpm as an option though for the jet engine effect!

 

[QuietBob]

Although the R5 has plenty of dust filters, it lacks them for the upper 5.25" drive bays and the top (which is why I'm not so happy opening it up for exhaust due to dust).

You could always MacGyver some kind of filter. That's what I did with my Define R4.

I used fine fiberglass mesh (the type used for mosquito screens) cut to size, and also installed aluminum filters at the top. Those have no fans mounted, and are simply used to facilitate convection:

 

[freeagent]

I run a filter free lifestyle, its better that way

Get a computer duster, it is very satisfying to dust whenever you want

 

[io-waiter]

I have define mini with dual 140 intake fans, it has mesh top panel with exhaust air flow restricted to behind the CPU cooler and a 120 low pressure, high volume exhaust fan. I also have an additional custom mesh cut out to the rear of the side panel to let the GPU exhausts out more easily. It works fairly well with a 8700K/2080/Vega amount of power.

Without restricting exhaust to the rear of the case much of the air flow from the intakes went out before cooling, path of least resistance. I use OH film/transparent plastic cut outs behind the mesh to restrict air flow where needed. As it is set up now air leaving the case will pass through heat sinks or over VRMs etc. Controlling the path of least resistance is key in cooling setups IMHO.

I also have a second fractal case more similar to yours with a 120mm bottom intake feeding cool air directly to the GPU and two 120mm fronts to keep air flowing through the case, it only has one exhaust fan, but it also doesn't need to get rid of much hot air.

 

[Ruru]

You could always MacGyver some kind of filter. That's what I did with my Define R4.

I used fine fiberglass mesh (the type used for mosquito screens) cut to size, and also installed aluminum filters at the top. Those have no fans mounted, and are simply used to facilitate convection:

View attachment 394558View attachment 394559View attachment 394560

Taking a pantyhose from the prettier one of the household for improved filter use works as well