Airflow advice for AIO & 5950x

[Cenuij]

I'm putting my new build together while I wait for a 5950x - currently musing over which orientation to place the AIO and case fans, would be happy to have some advice

Here's current setup with AIO top & current fan orientation.

I have another case fan but wondering if 4 intakes + 1 exhaust would be too much positive internal pressure for the AIO fans/rad setup as pull?

Would I be better having AIO/rad at the front as push intake?

Noise is a big factor as I spend a lot of time on work tasks without headphones on (hence the define 7 case), but I'm mindful that 5950x boost is temperature sensitive

 

[Pocket10s]

I would put the AIO on the front with the extra 120mm as an exhaust at the top.

 

[ttaskmaster]

I don't think it'd be too much.
I would put the extra in the front as an intake, and swap the top fans around to have them pulling as an exhaust, though. Pull traps less dust.

 

[Chris Ecob]

From the videos I've seen front mount always give better thermals and less noise. If your rad has screw mounts on the other side too then you can set it up as pull in the front. You'll need some shorter screws though.

In my system if I use a top mount intake rad (5 intake fans in total) then my GPU fans get quite loud when gaming. Having it set to exhaust gives me a quieter system as my case temp is lower but results in higher CPU temps as the rads drawing hot air.

Ideally I'd mount it at the front so it can draw cold air but still give good case airflow but it's a 360 and won't fit

 

[Mesai]

Best CPU thermals would be front-mounted, fans pulling cold air in, but will likely see the GPU temp increase.

 

[Chris Ecob]

Best CPU thermals would be front-mounted, fans pulling cold air in, but will likely see the GPU temp increase.

Yeah I guess if your not overclocking the CPU and/or it's running cool enough then top exhaust is best to keep GPU temps down. I like to overclock the CPU though so would prefer a front mount.

Top intake was terrible on my system though. Not conducive to case airflow especially if your running front intake fans as well.

 

[Cenuij]

Thanks, solid advice my dudes. I think I now want to avoid top intake for better CPU thermals.

I believe this Aorus Master allows individual fan control on each header, so I guess I can work out some profiles to balance temp/noise and try to keep slightly positive plenum pressure

aio/rad = front intake with 2x140mm pull
case = 3x 120mm exhaust (1 rear, 2 top)

Where along the top would you suggest I place the 2x 120mm exhaust?

 

[Chris Ecob]

Thanks, solid advice my dudes. I think I now want to avoid top intake for better CPU thermals.

I believe this Aorus Master allows individual fan control on each header, so I guess I can work out some profiles to balance temp/noise and try to keep slightly positive plenum pressure

aio/rad = front intake with 2x140mm pull
case = 3x 120mm exhaust (1 rear, 2 top)

Where along the top would you suggest I place the 2x 120mm exhaust?

That's what I'd go for yeah. Fans all at the top/rear so they're working to pull air through the case front to rear.

I think this is one of the videos I watched when I was trying to figure it out.

 

[pc-guy]

forget about what all them videos are saying. front mount your radiators, get it in a PUSH and PULL to get good airflow without increasing the air temp that much. then have 1 fan at the top and 1 fan at the reat as exhaust.

then you just need to play with fan speeds to optimise CPU and GPU temps vs noise.

 

[Bravetart]

Interesting. Sorry to hijack...I just mounted my AIO on the top, as that's historically been the best placement.

My Gigabyte 3080 Vision doesn't run hot at all (about 65 under load), whereas the 5900X seems to run quite hot, I suspect due to the boost pushing voltage quite high, so in theory, I would be better swapping to a front mount?

Using an NZXT H710i and Kraken Z73, so should have space for push and pull...but definitely should support 360 front mount in either push or pull. Would I then still be better with top exhaust, or would single 140 rear exhaust work?

 

[Chris Ecob]

forget about what all them videos are saying. front mount your radiators, get it in a PUSH and PULL to get good airflow without increasing the air temp that much. then have 1 fan at the top and 1 fan at the reat as exhaust.

then you just need to play with fan speeds to optimise CPU and GPU temps vs noise.

I found the video pretty useful to be fair. It's got some actual testing and a good detailed explanation of why the setup you're saying is best, is best.

 

[Jace007]

Great info, I'm planning to get the Arctic Liquid Freezer II 360 - (NZ gamer youtube review was very informative.) Also it has a fantastic price too

 

[ttaskmaster]

forget about what all them videos are saying. front mount your radiators, get it in a PUSH and PULL to get good airflow without increasing the air temp that much. then have 1 fan at the top and 1 fan at the reat as exhaust.

We were working on the assumption of the OP not having to buy anything further, as he already has another fan available...
Also, Push-Pull may not be especially useful on a 30mm AIO rad, or worth the extra expense of buying a second set of matching fans. It's far more of a thing on custom loops with 45+mm rads.

 

[pc-guy]

We were working on the assumption of the OP not having to buy anything further, as he already has another fan available...
Also, Push-Pull may not be especially useful on a 30mm AIO rad, or worth the extra expense of buying a second set of matching fans. It's far more of a thing on custom loops with 45+mm rads.

On thicker rads you will either need a set of really power fans or run a push pull. But thinner rads you can run push pull with less powerful and quieter fans and still get the same performance as a set of average fans.

for instance my rads comes with ML120. They are decent and powerful but I can pretty much replace those fans with anything I like in push pull without suffering any performance drop. And I can have my system running quiet.

without push pull you need to look at pressure optimised fans and they will become noisy even with the likes of artic P12 as you are effectively putting a blocker in front of it restricting air flow.

Furthermore airflow into the case (if rads are front mounted) is not as good when compared with push pull.

I am running atm P12 push pull and running at 900RPM and pushing my 3900x over 150w Power draw in Aida and OCCT and after a couple of hours the CPU is at 68c. And the whole thing is still whisper quiet. Also testing the GPU (2070s) with furmark, with the Arctic running at 900RPM GPU isn’t throttled or horrendous noise from it - can’t remember what temp it was but it was very reasonable. The exhaust from the case is a bit warm but nothing to worry about as every temp is well within range.

In the summer time I will ramp those fans up to 1150 or 1200rpm to get a bit more air flow going.

 

[Cenuij]

We were working on the assumption of the OP not having to buy anything further, as he already has another fan available...
Also, Push-Pull may not be especially useful on a 30mm AIO rad, or worth the extra expense of buying a second set of matching fans. It's far more of a thing on custom loops with 45+mm rads.

Actually your post has made me think a little about what's important to me in this build:

1. Noise
2. CPU Thermals

If I can reduce the noise (even by a small amount) while keeping the CPU temp the same I'd happily buy another couple of fans for push/pull.

The Fractal AIO has a spare PWM header in the hub (presumably because it's the same hub as the 360). Maybe the Arctic P14 looks like a reasonable push fan? If I get the more expensive model I can daisy chain them to use that single hub header - their RPM range and CFM doesn't look too different from the fractal fans.

I guess at this point I may as well get two more fans for the case - cheaper P14 without PST would work well, I'd plug these into the define 7 fan hub, that would leave 1 spare PWM header for future use if I wanted to use 3 case fans on lower RPM in future.

 

[ttaskmaster]

On thicker rads you will either need a set of really power fans or run a push pull. But thinner rads you can run push pull with less powerful and quieter fans and still get the same performance as a set of average fans.

Depends on the fan characteristics against the rad FPI, really.
Most thin rads (30mm and below) will tend toward high FPI, meaning more noise.
I run ML120s because they're still quieter than the Vardar 120ERs running at half the speed.

Maybe the Arctic P14 looks like a reasonable push fan? If I get the more expensive model I can daisy chain them to use that single hub header - their RPM range and CFM doesn't look too different from the fractal fans.

Is that what you already have?
If you're going push-pull, you need the same fans on both sides of the radiator.

 

[jamman]

I have an Arctic 2 and will be mounting it at the front.

 

[Cenuij]

If you're going push-pull, you need the same fans on both sides of the radiator.

I'll use the Prisma AL-14 PWM ARGB from the AIO on the pull side, I don't think there's a non RGB version available for retail for the push side. The RPM range, static pressure and CFM of the Arctic P14 is close enough that I can't see any major issues here.

If there turns out to be any issues or such I can put the P14's on a different header and make a custom profile in BIOS (Aorus Master) to adjust. Maybe I should do that anyway, I would think it's more efficient to have slightly faster RMP and hence CFM on the push side, would you agree?

 

[pc-guy]

I'll use the Prisma AL-14 PWM ARGB from the AIO on the pull side, I don't think there's a non RGB version available for retail for the push side. The RPM range, static pressure and CFM of the Arctic P14 is close enough that I can't see any major issues here.

If there turns out to be any issues or such I can put the P14's on a different header and make a custom profile in BIOS (Aorus Master) to adjust. Maybe I should do that anyway, I would think it's more efficient to have slightly faster RMP and hence CFM on the push side, would you agree?

That’s exactly right. Use motherboard programs to play around with fan speed to get the flow right in windows. Then you can fit that in bios.

 

[ttaskmaster]

Maybe I should do that anyway, I would think it's more efficient to have slightly faster RMP and hence CFM on the push side, would you agree?

I would not agree.
The higher CFM will just overload the lower fan and force it to work harder than it's meant to, while the lower CFM fan will introduce resistance against the higher fan and in turn make it work harder than it's supposed to.
This is why you need the same fans both sides. It's not just about setting RPM, as you need the same static pressure and airflow values, as well as flow characteristics. Otherwise they're just fighting against each other. At best, it is inefficient and you get all sorts of weird airflow interactions and annoying noises, and at worst you might damage your fans.

For example, if you have a fan with a wider airflow spread pushing in, that will slow the air and the pull fan will have to work harder than it's designed for, which could result in damage. Similarly, if you have too narrow a spread coming in, the airflow will batter off the pull fan, before creating a compression stall, and then batter back against the push fan, which is even more likely to damage them. In extreme cases this could blow the bearing and spray fluid over your components, or potentially snap some fan blades off and fling those around inside your case.