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

 

[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?

 

[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.

 

[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?

 

[Cenuij]

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.

Thanks, that's useful. I'll order a couple of extra Arctics so the rad has the same gear on both sides before I start on the profiles - can just move the fractal prismas' to case exhaust duty.

 

[Cenuij]

For what it's worth, I'm running a 5600x like this with the AIO set to 35% until 50c+. It only just goes above 50c in games. Corsair 4000X, 3x120mm intakes, Arctic LFII 280 exhausting, and an old Be Quiet fan on rear exhaust tied to GPU temp

I really like the white & black, looks great imo

 

[Cenuij]

OK, Arctic P14's arrived - these work well with the Fractal AIO, can daisy chain the PWM connectors on the fans and attach that to the PWM hub at the bottom of the AIO

In the areas I've circles here, is it worth closing off with something before I put the dust filter back on?



Previous Fractal case I had allowed you to open the top in segments, the Define 7 has a full replacement top so 66% of it will be just grill with a dust filter behind.

I can just use black electrical tape for the rear gap underneath the push fans, if it's even worth it.

 

[Cenuij]

You might find link below to basic guide of how airflow works and how to optimize case airflow of interest. It shows one of the remote senor thermometers I use as well as explains thing in more detail.
https://forums.overclockers.co.uk/t...-i-put-my-temp-sensor.18564223/#post-26159770

Thanks, the x570 Aorus Master comes with 2x temperature probes and 1x dB noise sensor.

I'll probably fix one temp probe to the GPU card somewhere, back plate under GPU maybe?

Not sue where to put the second temperature probe at the moment, maybe a good spot for this would be somewhere in the upper plenum to gauge air temp just before exhaust?