Question Best airflow

Ragnarlodbrok

Junior Member
Nov 29, 2021
6
0
6
Hello.

I am looking to buy better cooling for my pc.
I'm currently looking into a Arctic freezer II 360 aio.

However I am wondering about the effect and recommendations for airflow setup.

My current pc is :
Ryzen 5800x
Gigabyte Aorus B450 pro
2x8 Corsair Vengeance LPX 3000 black
Rtx 3070 FE
Fractal design define R5 case.

I will put the AIO as a top exhaust due to space.

I will have 2x140mm fans and 1x120mm fan available.

What would be the best setup for the case fans?
 

Paperdoc

Platinum Member
Aug 17, 2006
2,108
195
106
The most common advice here would be to mount the two 140mm front fans as intakes, the AIO rad system at top as exhausts, and the rear 140 mm fan as exhaust. The case comes with two fans and you say you intend three, so I presume you will buy a third 140 mm Fractal Design Dynamic GP-14 fan to match the other two. NOTE that those fans are of the older 3-pin design that requires Voltage Control Mode (aka DC Mode) set for the mobo SYS_FAN headers you use. It is not advisable to mix 3- and 4-pin fans in your system, especially not together on one header.

In case ventilation one wants near-balance of intake and exhaust fan capacities. In reality, of course, there is one firm rule: what goes in must come out. And you really can NOT know or calculate real air flow balance from capacity specifications, but they are good guides. My own preference is that there should be slightly more intake capacity so that the interior of the case is at very slightly higher air pressure that outside; this means air LEAKAGE at cracks will flow OUT of the case and prevent influx of dust. Of course, that also assumes that all intake fans will have dust filters in front of them (included in your case's design). Given those considerations, the "common advice" above will result in two front fans as intakes (capacity slightly reduced by dust filters) versus four exhaust fans - three on the rad (a significant flow reducer) and one unrestricted at the rear. Air flow overall will be good this way. But air flow balance is likely to be too much exhaust capacity. IF you want to address that, one way would be to connect both the front intake fans together to one header and configure a custom "fan curve" for that pair to run them faster than "normal" so that they keep up with the total exhaust capacity of the other four. Another option, though, would be to take advantage if the optional fan mounting location in the left side panel. Buy a fourth fan of that same 140mm type and mount it there with a dust filter. Connect it also to the same fan header with the front pair (use a simple Splitter) and let the header use the default "fan curve" for that group. This gives you a bit MORE total air flow (some of it directed into the space where the graphics card is) with three intakes and four exhausts, but the top rad fans are more restricted (in terms of air flow) than others. The likely result is a good balance with small positive air pressure inside the case.

If you need more details of how to use a Splitter, and the distinction between a Splitter and a Hub (you do not need a Hub), post back here.

I have assumed you will NOT use the fan speed control device mounted in your case. That is a simple manual switch on the front where you can plug in three case fans. With that YOU have to monitor your system temperatures and decide when and how to set fan speeds. It is much more convenient to have the fans' speeds controlled automatically for you by mobo SYS_FAN headers that are configured to use a temperature sensor on the motherboard (not the one inside the CPU chip) for guidance. Now, on SOME cases equipped with fans and a manual control button, the connectors on the fans' cables are non-standard and can't be plugged into mobo headers. I am assuming that will NOT be a problem for you with this case and fan set.
 

Ragnarlodbrok

Junior Member
Nov 29, 2021
6
0
6
Hey.

Thanks for the detailed answer.
Actually the 3rd fan will be a 120mm noctua (unsure of model but dating back to <2010.
It is currently attached to my cpu cooler and will become available.

I suppose it would be better as the exhaust fan to ensure higher intake.

If I have 2x140 front intake, 1x120m rear exhaust and AIO exhaust, do you recommend an additional 140mm fan as a bottom intake? If so, can you recommend a fan (3 pin if I have followed correctly)?

Concerning the manual Vs auto, I will be leaving everything on automatic.
 

Paperdoc

Platinum Member
Aug 17, 2006
2,108
195
106
Check the Noctua fan. IF its cable has THREE wires and ends in a connector with three holes, then it's a 3-pin fan and can be controlled in the same way as your two Fractal Design fans. But IF it has 4 wires and pins, it is of the newer PWM design type, and for that it should be connected to a different mobo SYS_FAN header that is configured to use PWM Mode for control, not Voltage Control.

With that difference, yes, place the Noctua as the rear exhaust and have the Fractal Design 140 mm pair in the front as intakes.

If you are getting a fourth fan, I suggested using the left side panel mounting location for that just because I prefer side over bottom. That's mainly for unobstructed air flow and some concern for dust intake. But that's not a firm requirement, so if you prefer bottom mount, go ahead. Which fan? I suggest a 3-pin model just to match what you have. Another Fractal Designs would match perfectly, but other fans also would do well. I do have a bias in favour of Noctua fans - they are good, quiet, last a long time.
 

Hans Gruber

Golden Member
Dec 23, 2006
1,469
556
136
I have a Be Quiet case with 3x 140 fans. The AIO watercooler is on the roof and both those fans 120mm are setup as exhaust. The 140mm on the back of the case is exhaust. Heat rises so I use the top front of case case fan as an exhaust and the bottom front 140mm case fan as an intake fan. A case with good air flow is just as important as your cooling solution. 140mm fans are quieter than 120mm.
 

Ragnarlodbrok

Junior Member
Nov 29, 2021
6
0
6
Thanks again for the detailed answer.
Huge help.

I just checked, my noctua fan is a Nf-p12 3 pin.

I think I'll go ahead with the AIO (unless you recommend the D15 for my setup)
Setup 2x140 front noctua 120 rear invest in a fan for the bottom (I really don't like the idea of a cable attached to the removable side, I just know I'll forget about it one day and tug the cable)

Last question, would I get much of a benefit if I swapped all fans to 140mm 4pin noctua ones (I too like their quality)
 

Paperdoc

Platinum Member
Aug 17, 2006
2,108
195
106
No real big benefit. Many makers (Noctua included) make fans with either 3- or 4-pin motors, but identical performance. The advantages of 4-pin PWM over 3-pin Voltage Controlled are mainly:
(a) 4-pin can be run at lower minimum speeds without risk of stalling;
(b )You can start up a stalled 4-pin at a lower minimum speed signal than a 3-pin. This last, however, is of little use because a normal automatic fan control system will always START a stalled fan at nearly FULL power, then slow it down to required speed.

Those advantages are small if your mobo gives you the option (as most do today) of using the proper Voltage Control Mode (aka DC Mode) required by 3-pin fans for fan speed control signals. I think keeping them all one type to avoid confusion is easier.

there is one other factor that is NOT pertinent to your situation OP. IF you are using MANY fans and have few mobo SYS_FAN headers to connect them to, a fan HUB is the right way to do that. However, in almost all cases, to use a HUB (which draws power for fans directly from the PSU) you MUST be using ONLY 4-pin PWM fans and you MUST connect the Hun to a mobo header using the PWM Mode for control. You can't use a HUB with 3-pin fans - only a Splitter can work with those.
 

Ragnarlodbrok

Junior Member
Nov 29, 2021
6
0
6
Thanks yet again.

I think I'll see about getting the aio and an extra 3pin fan then.

Just gonna take some time to see if I discover any AIO which cool better than the Arctic freezer.
 

aigomorla

Cases and Cooling Mod PC Gaming Mod Elite Member
Super Moderator
Sep 28, 2005
19,622
1,999
126
Have the AIO roof mounted pull air from outside into the case.
Have a front fan sitting in front of your gpu, well, sightly below so it can pull fresh air into the intake of the gpu.

Have a rear exhaust fan to blow out of the case to keep airflow uniform.

The rest is sort of moot, the define is a great case with good air flow.
Just remember you want new source air to be fed to your components which need cold air but at the same time, you do not want all your fans pulling air in as it will just jumble recycled air though out the case.
 
  • Like
Reactions: Ragnarlodbrok

Ragnarlodbrok

Junior Member
Nov 29, 2021
6
0
6
Oh wow, almost the complete opposite setup to the previous answer..

Suppose that gives me a couple of options.
Also have the possibility to mount some Arctic p14 that I can get cheap.

Do either of you have experience with the well known hot running 5800x? This seems to be the component I need to keep my eye on.

Side question. Is there anyway to keep the case quiet with the top mounted AIO (I assume there's no way to leave the moduvent panels on?)
 

Paperdoc

Platinum Member
Aug 17, 2006
2,108
195
106
I think aigomorla's advice is aimed at two goals. One. as said, it to get as much outside air into the case as possible. But that ignores the fact that it must also be able to LEAVE. If it can't leave, it cannot enter no matter how many intake fans you use.That is why you aim for near balance between intake and outflow. The other factor is ensuring the lowest temperature for the air cooling the rad. Normally the temperature of air inside the case is not a lot higher than the outside (unless you have very poor ventilation), so there is a small difference in CPU cooling using an AIO between having the rad as intake or exhaust.

Your side question: definitely do NOT place those panels over the rad! The whole point is to have the LEAST possible resistance to air flow at that point. Your key concern is HEAT, not noise.
 
  • Like
Reactions: Ragnarlodbrok

Ragnarlodbrok

Junior Member
Nov 29, 2021
6
0
6
The 3-4 intakes vs AIO and 1 rear exhaust seems more inline with what I was thinking.

I think I'll try it first, and if I see CPU is too hot I'll switch around to try aigomorla's solution.

I'll try to remember to leave feedback here, but it'll be after Christmas as I won't have time to install the AIO before.
 

ASK THE COMMUNITY