Build Advice Fan setup for the Fractal Design North XL (mesh version) case ?

[T44v1]

Hey guys

I have mostly picked out the parts for the new PC I am building, but I was curious about the fan setup I should be using. This is the first PC I will be building for myself, so I am relatively new at this.

My PC case will be a Fractal Design North XL (mesh version). I'm thinking of using: one arctic p14 max fan in the rear as exhaust, 3 in the front as intake and then 3 arctic p12 max fans for the AIO cooler up top as exhaust.

The issue I see here is that if all fans operate at the same strength, then I might end up having negative air pressure in the case. Would it be enough of a problem that I should try and rectify it by removing a fan or two or, alternatively, powering either of the exhaust fan setups down? Any advice is appreciated.

Here's my build list in case you need the extra info: https://fi.pcpartpicker.com/user/T44v1/saved/8txhjX

08/02/2025 edit: swapped out the mesh case version for the tempered glass one

10/02/2025 edit: The actual aio cooler I am planning to use is the Arctic Liquid freezer III 360. I updated the list to reflect the correct info.

 

[Lutfij]

Is the AIO you've listed in the PCPP link the first version? If yes, how old is the cooler? If no, you might want to to look into the Liquid Freezer III and the fans on it are actually good.

To get on topic with the thread's question, yes the fan setup you're thinking of should work. I would leave the rear fan mounting option blank and see how temps are.

 

[T44v1]

https://fi.pcpartpicker.com/product...iii-360-563-cfm-liquid-cpu-cooler-acfre00136a
It's this one.

 

[Phaaze88]

Hey guys
...
The issue I see here is that if all fans operate at the same strength, then I might end up having negative air pressure in the case. Would it be enough of a problem that I should try and rectify it by removing a fan or two or, alternatively, powering either of the exhaust fan setups down? Any advice is appreciated.

Here's my build list in case you need the extra info: https://fi.pcpartpicker.com/user/T44v1/saved/8txhjX

There's no pressure in the variant of the North with the mesh side panel. There actually needs to be some degree of air restriction for pressure buildup inside a case to be a thing. Too much open surface area, and there's no pressure; the air entered as easily as it exited, or vice versa.

I'm thinking of using: one arctic p14 max fan in the rear as exhaust, 3 in the front as intake and then 3 arctic p12 max fans for the AIO cooler up top as exhaust.

That's the general recommendation. You can just do that.

 

[dwd999]

Since its the mesh version of the case I would consider adding fans for the Accessory Fan bracket mounted over the gpu as long as it does not interfere with the gpu's power cable connection.

 

[Paperdoc]

The discussion over positive or negative pressure in a case really has almost nothing to do with cooling performance. It is all about DUST control. IF you arrange to have more intake capacity than exhaust and IF ALL those intake fans have cleanable dust filters on them and IF your case is sealed up except for fan openings, then only filtered air can enter, and any air leakage at small cracks is outward. In your case, as you anticipate, you may have negative pressure allowing air influx at UNfiltered entry points. But the biggest of these is the mesh side! Unless you plan to rig a huge dust filter there, there WILL be unfiltered air entry.

dwd999 has an interesting idea. It is possible with that case to mount two additional intake fans on the mesh side IF you ALSO obtain (from Fractal design directly?) an adapter for mounting them. I would assume you CAN fit mesh dust filters in front of those two fans to prevent dust intake. CHECK with Fractal Design whether the system for added side fans allows filter mounting, too. Aside from added cooling for your video card, such a fan pair will increase total air intake capacity so that the case IS at a very slight positive pressure and leakage though the mesh side will be outwards.

 

[dev_cyberpunk]

The issue I see here is that if all fans operate at the same strength, then I might end up having negative air pressure in the case. Would it be enough of a problem that I should try and rectify it by removing a fan or two or, alternatively, powering either of the exhaust fan setups down? Any advice is appreciated.

Should be ok.
The three 140mm fans in the front pushing in at 95 cfm each is going to provide enough air to go through the case and exhaust out through 3 120mm fans at 82 cfm.

The only thing is you don't need a rear exhaust, and the case you picked is not designed really well for exhaust fans in the back in the first place.

Even though I would use better intake fans by default it should work in most environments with those low end fans. I use Iceberg Thermal IceGale Xtra fans for case fans. So the 140mm fans I would stick in the intake would be 169 CFM.

 

[T44v1]

Well, if I also add two intake fans to the side bracket (with a potential dust filter), that should turn the overall air pressure positive, all things considered. But, assuming that I fill up all 8 fan slots (3 140 mm intakes to the front, 2 140mm intakes to the side bracket, 1 140 mm exhaust to the back and 3 120 mm exhausts on the aio cooler up top), Would the arctic p12/14 max fans be enough for a balance of noise/cooling depending on the fan curve, or should I upgrade the intake fans to the iceberg thermal icegale xtra-s?

 

[dev_cyberpunk]

Well, if I also add two intake fans to the side bracket (with a potential dust filter), that should turn the overall air pressure positive, all things considered. But, assuming that I fill up all 8 fan slots (3 140 mm intakes to the front, 2 140mm intakes to the side bracket, 1 140 mm exhaust to the back and 3 120 mm exhausts on the aio cooler up top), Would the arctic p12/14 max fans be enough for a balance of noise/cooling depending on the fan curve, or should I upgrade the intake fans to the iceberg thermal icegale xtra-s?

Looking at the case, you would have to tape up the mesh side to even establish air pressure to cool with forced air cooling. No side fans are needed.

There will be a loss on the fans blowing through the radiator so the exhaust is not going to be ~90 cfm it will be about %20 less than that. So you will have enough air column to cool the rest and exhaust out the back, provided that you tape up the mesh side they should have made a changeable panel for different setups. I use aluminium tape that is used for ducting for that.

You can use the fans you selected however, if the room its in gets hot it may not have enough air flow to cool it off. That is why I run aggressive fans. I don't run air conditioning in the summer.

 

[T44v1]

Then would it be better to just take the tempered glass version case and go with higher powered fans? I'm guessing that the iceberg fans are louder, but the glass would cover up the extra noise that comes with them

 

[dev_cyberpunk]

Then would it be better to just take the tempered glass version case and go with higher powered fans? I'm guessing that the iceberg fans are louder, but the glass would cover up the extra noise that comes with them

They usually are not loud unless you run them full speed or you have obstructions. But normally I run them 500-600 rpm. But you will be just fine with what you got too unless you want to run it in a 90 degree room.

 

[T44v1]

Okay, i think I'll go with the arctic p12/14 maxes in the tempered glass case, then. Are you sure that I am better off not using an exhaust fan? Will the AIO exhaust make up for it or is there a downside to not venting any hot air from the rear?

 

[dev_cyberpunk]

Okay, i think I'll go with the arctic p12/14 maxes in the tempered glass case, then. Are you sure that I am better off not using an exhaust fan? Will the AIO exhaust make up for it or is there a downside to not venting any hot air from the rear?

AIO exhaust will vent some of the air getting pushed in then the remaining gets push out the back. Problem when having too many exhaust zones you can induce null spaces of air. So if you get cooling issues, add a fan in the back to push in. You basically have a hole in the top of the case covered by a radiator and fans, so there is no issues of exhausting. So if you have cooling issues, it is going to be from supplying air into the case.

Tempered glass vs mesh side make little difference but the mesh side case can house a bigger system than the tempered glass one if you need to induce side cooling. If I was building this for gaming I would get the mesh side case so I have more cooling capacity for future things like a big video cards.

 

[T44v1]

Okay, I think I have mostly enough info for now. Once I have the pc built (which should take a week or two, depending on how fast the parts arrive), I'll try out not using a rear fan in the beginning, and if it doesn't work out, I'll put it in as well, as either intake or exhaust, depending on which is better for cooling/pressure.

 

[dev_cyberpunk]

Okay, I think I have mostly enough info for now. Once I have the pc built (which should take a week or two for the parts to arrive), I'll try out not using a rear fan in the beginning, and if it doesn't work out, I'll put it in as well, as either intake or exhaust, depending on which is better for cooling/pressure.

If I ever use it, I rarely set a rear fan exhaust because it has a tendency to create a negative space near the end of the motherboard. That is why the rear fan should be tried after the initial build to evaluate its usefulness.

 

[Paperdoc]

I'm going to disagree a bit, but first an item to clarify. The web page for that case actually promotes TWO different cases - the North and the North XL cases - that are different sizes. EACH of those also comes in two variants- solid or mesh left side. At first I was confused and started to warn you that the smaller North case will not allow a larger AIO rad at the top. But then I realized all the details and you are getting the XL version that is larger all around.

Regarding the rear exhaust fan, YES, you do need that. It is certainly true that what comes in must go out, so having NO exhaust fans or few means that the air brought in from the front WILL be blown out, and some of that will exit via the rear opening even with no fan there. But any added fan will increase the total air flow, so including the rear EXHAUST fan will make your overall cooling a bit better.

As to balance and internal pressure, running all of those fans at basically the same speed might well create a small negative pressure at first glance. BUT the top rad fans are blowing through the rad fins, so that reduces their actual air flow as dev_cyberpunk said. Further, those are 120 mm fans whereas you plan 140's in the front and rear. Without the rear at all, you most certainly would have more intake capacity than exhaust, and thus a positive internal pressure. Add the rear exhaust as 140 mm size and you might get slightly too much exhaust and small negative pressure, but maybe not. ONE way to reduce that exhaust capacity at the rear would be to use a 120mm fan rather than 140, and that would get you very close to balance.

After you have this all assembled and working you can test and tweak. To start, ensure that the REAR fan is connected to its own mobo fan header so you can customize its "fan curve". Then set up for testing by smoke tracing. You need a small smoke source like a smouldering incense stick or cigarette. With your system running at idle, move the smoke source around the outside of the case near small cracks where air leaks and observe the smoke movement. If it is sucked into the case, that's what the dusty air will do. If is is blown away from the case, you have positive pressure inside and that keeps dust out. If it moves very fast (one direction or the other) the pressure is too high and needs some adjustment. Now repeat with the system busy on some medium or high workload, and see how the smoke moves.

With that information you can go into the configuration details for that particular mobo fan header that the REAR fan is connected to. For the mobo you listed you can download the UEFI BIOS manual here

https://download-2.msi.com/archive/mnu_exe/mb/AMDAM5BIOS.pdf

See p. 46 for how to adjust a fan. Select the correct header at top and look at the graph below of fan speed versus temperature. If you need to adjust the rear fan for less speed (less air removal) at low or high temperatures, just move the round dot down a bit. MAYBE do a smaller adjustment to the next dot. When done, use the F10 key to pop up a mini-menu for Exit (see p. 24) and choose Save and Reboot to save your changes. Now re-test with the smoke flow to see the result. You can repeat this all if the result is not what you prefer. You are aiming for smoke to flow AWAY from the case slowly under most operating conditions.

 

[Paperdoc]

I just remembered a small item you should know, OP. MSI does one thing a little different on their mobos. For all of the SYS_FAN headers, they set their MODE by default to DC Mode. Assuming all your fans are newer 4-pin PWM types, you should change that setting for all your SYS_FAN headers to PWM. It's on the left side of the same configuration screen (page 46 of the manual). The default for the CPU_FAN header will be PWM already.

 

[T44v1]

Thanks for the heads-up. I'll need to look a bit more into how connecting the fans onto the motherboard works, since this is something I haven't done before previously.

 

[Paperdoc]

A quick guide for fan connections, then.

All mobos have two main types of fan headers. Electrically and mechanically they all are the same - the difference is in what and how they control their fans. All of them operate by using for input info the TEMPERATURE at a relevant sensor, and a "fan curve" to decide what speed to run the fan for the current temp. How that fan speed decision is made (the Strategy) is the PROFILE setting in a fan header configuration. Although we talk of fan speed control, this really is a TEMPERATURE control system that aims for a temperature, and manipulates fan speed to achieve the goal. After that decision is made, the MODE setting is how the signals are sent out to the fan to get that speed. MODE may be Voltage or DC for older 3-pin fans, PWM for newer 4-pin fans, or sometimes "Auto" so the header can test the connected device and set itself to the correct one. In general, "Auto" can cause problems because its testing system is weak, so you would be best to ensure this is set to PWM for the fans you have. All fans have the same female 4-hole connector on their cables. It has two ridges down one side, and holes 1-3 are between these. The mobo header has 4 pins with a plastic finger sticking up beside Pins 1-3, so the connector fits onto this header only one way.

One header group is solely for cooling the CPU chip, and it includes the CPU_FAN, any PUMP_FAN, and any CPU_OPT headers. All of these use only the temp sensor built into the CPU chip by its maker. CPU_OPT is merely a mirror of CPU_FAN so you can connect more than one fan to this control signal. PUMP_FAN is only for use with the pump unit of most AIO systems, but you will NOT use it with the Arctic Liquid Freezer II 360 AIO system you are getting. Many AIO systems have separate cables from their fans and their pump. The Pump is intended to run full speed all the time, so it connects to the PUMP_FAN header that gives it full power at all times and NO speed control signal. The rad fans connect to the CPU_FAN header that controls their speeds. But your Arctic Freezer system is designed differently with only one cable from the pump unit that MUST go to the CPU_FAN header. That controls the rad fans, and the system uses its own internal method to adjust the pump speed according to heat load. All connections to the rad fans are supplied with the system.

The second header group is the SYS_FAN headers used for case ventilation fans. These often have an option in each header to choose whether the temperature sensor it uses is the one inside the CPU chip (in case you are using this header for something related directly to the CPU), or a different sensor on the mobo. In your case you will be using these headers only for your three front case intake fans and the rear exhaust fan, so ALL of these headers should be configured to use the motherboard sensor (again, p. 46 of the manual, left hand side), PWM Mode, and the default "fan curve". Since the mobo has six SYS_FAN headers and you are using four case fans, you can simply connect each fan to its own header, all of them being configured to do exactly the same thing. Exception: as I suggested above, AFTER you have this all set up and running, you can do the smoke flow testing and "tweak" the fan curve for only the one header that controls the rear exhaust fan.

 

[T44v1]

Wow, this is such a detailed description, thanks for that, and the warning regarding which fan header the aio pump cable must go to. Though I must note that I mistakenly added the wrong cooler to my PCPP list, and I am actually planning to use use the Arctic liquid freezer III 360, not I or II. Does that somehow change the fan header I must connect the AIO pump to, or is it still the CPU_FAN?

 

[Paperdoc]

Only slightly. The III model offers you two choices for how to connect, and that means choosing which of two cables to connect between the pump unit and the mobo. I recommend the simpler option of the "all in one" cable in only one piece, and not the one with three separate arms to mobo headers. The three-armed unit is only for people who intend to tweak all parameters on CPU cooling for maximum personal control, and that is not suitable for a regular user or a newcomer. The simpler cable just goes to the mobo CPU_FAN header.