4000x Top Mounted AIO Question

[DrGizmo]

Hey Hivemind, 

Need some advice; I'm working on a new build. Specs as follows:

Chassis: 4000x

CPU: Ryzen 5950x

Mobo: ROG Crosshair VIII Dark Hero

Ram: 32 Gb Trident Z Neo

CPU Cooler: Ideally I would love to top mount the H115i Plat or similar 280mm AIO

The Question: I know the RAM slots are a bit lower on the VIII Dark Hero. Does anyone know if Ill have enough clearance in this case to get a 280 mm AIO top mounted? 240 mm wont cut it for this CPU, and i dont want to front mount the AIO, as the case already has pretty poor airflow, and that will make it even worse. Any suggestions are greatly appreciated!

[Corsair Perd]

It's certainly possible depending on the motherboard. Paul's Hardware did a build with an MSI MAG B550 Tomahawk; if you refer to the timestamp below, you can see that the memory is tucked under the fan.

Unfortunately, without either motherboard in hand, I can't give you a definitive answer.

 

[DrGizmo]

bumping this, as still trying to figure out if i can top mount an H115i Capellix with a Dark Hero VIII, Trident Z Neo, or will RAM clearance be an issue? Im pretty sure the DIMMs on the Dark Hero VIII are lower than standard, no? 

[c-attack]

I will be very surprised if it fits up top.  The 4000 series has a fairly common "shallow top" design for mid towers.  Both height and the extra 20mm of width are likely to be a problem.  It might be possible on a 5000 series, but I would rather someone with both pieces in hand confirm.  Most likely any 280mm size radiator is going to need to go in the front.  If you watch the original video linked above, you can see the issues.  

Edited September 22, 2021 by c-attack

[DrGizmo]

Thanks c-attack. I guess my next question would be then, if i go H150i mounted in the front as intake, and two top 120's and a rear 120 as exhaust, how would the thermals be? Im worried about blowing the hot air from the radiator into the case, and also worried about the airflow in general through the rad with the glass front of the 4000x.

Am i in general just better off going 5000x with 360mm rad top mounted, 6 intakes in front and side and 1 rear exhaust? Im not a fan of the 5000x due to the enormous size, but i guess if thats my best option?

[c-attack]

Using the radiator as front intake does not automatically heat up the case. The air coming off the radiator will be approximately equal to the coolant, so typically 26-36C depending on room temp and cpu load. The actual heat added from the cpu is going to be fairly low. You might see a 4C coolant rise during gaming, but that does not mean the case temp goes up 4C in the critical areas. A lot of that goes straight out the top. 
 

Meanwhile the only thing that cools your gpu is the gpu’s own fans. The front case fans aren’t really doing that. The gpu radiates heat. The exhaust fans help remove it. Case temp goes up if you don’t. If the front fans can’t supply enough intake air through the radiator (likely), then air will be pulled in from any available path like case gaps etc. This isn’t a bad thing and will help with the general cooling air flow path. 
 

With a bigger case and a 240 or 360 up top, you may be able to blow more air at the gpu, but then you will also be removing some of that heat through the top radiator. So you might knock down the gpu top plate temp by a 2-3C, but then you likely will see higher cpu temp because the coolant up top may run 4-6C higher than it otherwise would. The top of the case is often 2-3C warmer than the front rail without load. Adding the gpu waste heat will further increase that. 
 

So the answer may depend on which component you wish to prioritize and if 2 inches more of external case space is worth giving you 2 more inches of internal space. As for the front glass effect on thermals, it usually depends on the offset space between glass and fans. Someone with that case or a professional review might have specific info. 

[DrGizmo]

Thanks c-attack, this is an excellently informative answer. This is exactly the type of info I was looking for and youve helped me settle on a decision Ive been debating for a long time! 

Based on your explanation, I think Ill go ahead with the 4000x (i prefer a smaller form factor), with an H150i front mounted and 3 exhaust fans (1 rear, 2 top). Sounds like that should work well. Thanks a million!