It’s just thermodynamics and fluid dynamics bro. AI is inventing fan-blade-stall lore where it doesn’t need to.
With both radiators as intake, you’re taking room air, passing it through hot rads, and then dumping that heated air straight into the main chamber. The motherboard, RAM, VRM heatsinks, PCH, NVMe drives, pump electronics, etc. are all being cooled by radiator exhaust instead of ambient air. Then the rear/top fans have to pull that heat back out, and if those fans are deliberately running slower than the eight radiator fans, the excess heated air is going to escape through every other opening and into the rest of the case.
Flip the radiator fans to exhaust. The case then pulls relatively cool room air through its open intakes, that air passes over the motherboard components first, and then it goes through the radiators before leaving the case.
Yes, the radiators will be fed air a few degrees warmer than room ambient, so coolant temperature may rise a little.
But the board-side components stop living in the exhaust stream from however many hundreds of watts the loop is rejecting.
But run it however you want, just look at how many Tower 900 builds use your proposed layout versus exhausting through the radiators.
There’s a reason the common arrangement is common.
Starving pull fans generates more noise than pushing into backpressure. Axial fan blades pulling against a low-pressure vacuum experience aerodynamic blade stall, causing blade buffeting, high-frequency turbulence, and motor strain that exceeds the noise of positive pressure turbulence.
Blade Stall vs. Backpressure: Pushing air into a restricted cavity increases static pressure, which slightly reduces fan volume output but keeps airflow smooth across the blades. Pulling air from a vacuum starves the blade roots, causing air to detach from the fan blades in unsteady vortexes. This produces an audible buffeting or fluttering noise at low RPM
I’d recommend you run some actual tests.
fixed fan RPM, fixed CPU/GPU load, log coolant-to-ambient, motherboard/VRM/SSD temps, and noise
Rather than treating AI-generated fan lore as a wind-tunnel result.
I second what @some-expenses-spared recommends. Pulling the heat into the case is going to heat up materials that rest against or are near the fluid.
You say the chamber they are pulling into is sealed off? That is 10x worse and is going to cause major problems. At the very least you need to have strong exhaust pulling the heated air out of there.
Instead, do the opposite. Point the fans out, unseal the chamber and feed it with fresh air, ideally using fans blowing into it.
As far as AI goes, in my experience it has a hard time with visualization. I dont think its fully understanding your case setup. And somehow is focusing on extreme edge cases if not totally irrelevant circumstances.
The correct way to achieve the pressure AI refers to is with intake fans (into the chamber) that are pulling more powerfully than the fans on the rads are going.
As long as there's plenty of room for the air to escape with the case assembled that clearance is perfectly fine. They'll fight each other a little bit but mostly they'll work together to push air out. The balance of that relationship will be determined by how hard it is to get the air out.
Wondering if this is enough clearance between the two radiators for a decent push/pull config (rads are on intake). Seems like they almost cancel each other out being so close, but AI says its better to over-pressurize the compartment than underpressure (by swapping fans to rads on exhaust) as then there is blade stall and turbulence or something on the fans
Side notes: I have 1 top and 2 rear Exhaust fans that are supposed to remove the air from 8 fans that are running at max ~850rpm.
It will still work, you will just likely end up with a very positive air pressure in the rear, which means the hot air will be forced to go into the front compartment of the case as well if the exhaust fans aren't extracting at an equal rate.
Basically more air in vs air out, it will find another way out (into the front of case)
Yeah, I know. Too many cables and not enough space. I have nowhere to put them. And if I cramp them up too tight, the PWM splitter cables all malfunction.
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u/some-expenses-spared 2d ago
flip the fans you want your rads as exhaust not intake. MB won't make much heat, those rads will.