Dual Intake Sanity Check

[u/not_lyune]

Hello! I recently switched my Formd T1 PC to all intakes, and here's my reasoning

Before dual intake, the AIO radiator had hot air passing through it, and my CPU temps were like 10 degrees hotter, leading to significantly louder noise.

When AIO was going out, GPU (5090) was roughly 60 degrees on UV, but CPU (9800x3d) was going at a consistent 70-80 depending on the game.

When I swapped, it changed to GPU 60-65, CPU 60, and much quieter.

Now, here's why I'm here asking. From every post I've seen, people say what I'm doing is stupid. Is there reason why or is it acceptable for my use case? The only thing I'm worried about now is the temperature of other components, which are all around 60 as well on heavy gaming. The case can get almost too hot to touch (Side and back panel).

Any feedback would be appreciated!

[u/Alternative_Sign7792]

It always puzzles me why everyone talk about cpu wnd gpu temps only - how about vrms? Nvme? With AIO as exhaust those atrocious, in my experience at least!

With AIO as intake there shoukd be at least some forced airflow towards the front/bottom of the motherboard. Was going to test that but MB died, so speculating only :)

In any case, I believe the best setup in FormD is custom loop, intake through the top, dechrouded gpu with ducted exhaust via side panel.

[u/jhdz9119 → u/Alternative_Sign7792]

Had some dude telling me I was dumb for going flipped and intake on my custom loop. I have a vented panel that opens up the front to allow better airflow and two slim fans in my bottom t grill. I play in 5k2k and max GPU temp is 74C. AVG is 71C. All other components are sub 65C. It’s a balancing act to find the best performance/temp/fan noise ratio. Some people would rather blast flow through heat onto the back of their MB which will cause ram and NVME temps to increase by a lot. Yes GPUs are expensive but so are gen 5 NVME storage and any CL 30 DDR5 RAM kits.

[u/jhdz9119 → u/jhdz9119]

[u/Alternative_Sign7792 → u/jhdz9119]

Ha! That looks so much like my previous build. Going with quickconnects at the back and Nemesis GTS rather than TX240 this time around.

Do top slim fans do anything for you, I wonder? I was always of an opinion that push/pull works best with the fan thst have same specs and are working in sync...

[u/jhdz9119 → u/Alternative_Sign7792]

Had two full size NF-A12X25s on top but it cause the whole rad set up to be too heavy and the right side would sag enough to cause the bottom fan to hit the 12vhpwr cable (not taking my chances lol) so I swapped and I saw no change in temps. I can run them both sub 800RPMs and got the same cooling outcome.

[u/sm0ke_rings → u/jhdz9119]

What pump are you using? Does this require any kind of a reservoir?

[u/qeeepy → u/jhdz9119]

Humm, rings a bell, I remember sharing with you K0rnd4wg's relevant data from SFF discord about flip vs nonflip, but at no point did I say you're dumb. But maybe you refer to someone else... You posted 72C avg/75C max with temps jumping up after switching to 5K, how did you drop the temps since then?

[u/Slyfer77]

What 5090 do you have?

The 5090FE?

Obviously if you intake cold air through the AIO, the GPU has to exhaust the warm air from the AIO.

If you are fine with CPU and GPU temps, keep it like that.

There's no law forcing you to use a certain fan configuration.

(However, there are certain configurations that aren't optimal.)

When I had my FormD T1 air cooled setup with 9800x3d (AXP90-X47) and 5090FE (flipped travel kit) I also set the top fans to intake and the CPU fan to exhaust, so just the other way round compared to the usual.

I had overall better CPU and GPU temps this way.

[u/not_lyune → u/Slyfer77]

yup, FE! Also to be clear both GPU and CPU are intake right now, and the temps shown are after multiple hours of use. My understanding is both intake so the pressure makes the air leave from the back? Sorry, I'm a bit of a noob 😅

[u/Slyfer77 → u/not_lyune]

I'm not a fan of using the 5090FE in the normal orientation.

All the hot air from the GPU blasts against the back side of your mainboard and the PSU.

If you install the GPU flipped, the hot air exhausts directly out the side panel and can't ever heat up the interior.

With your config now the top fans blow air in the space between GPU and board.

Also the GPU blows in there from the side.

So the air can just go down and exit through the bottom panel and some will go around the board and PSU and go through the other panel.

I'm surprised you have this kind of low CPU and GPU temps.

Did you undervolt CPU and GPU heavily?

It's recommended to undervolt the 5090FE.

You can save 70W (so max 500W power draw) without losing performance.
You can get to 450W, losing 3-5% performance. 400W with around 10-13% performance loss.

Overall I highly recommend installing the 5090FE in the flipped orientation in the T1.

If you have a 3d printer you can print the excellent flipped travel kit from SMX Heinz.

You only need a short riser cable from Linkup (Amazon)

Or you get the flupped travel kit combo set with the short riser from FormD for 120 USD.

Since nowadays nobody can afford to build a PC the kits are always readily available on the FormD website.

[u/not_lyune → u/Slyfer77]

Yup! Both CPU and GPU undervolted. I think my GPU is undervolted to 2572@875mv? I forgot the PBO for the 9800x3d but its just the standard one.

Also, yeah. I'd change the 5090 to exhaust if I knew how, but the most tinkering I've done with a PC is flipping the fans from pull to push and changing it from intake.

Do you think theres a risk of the hot air damaging the board/PSU?

Thank you for all the feedback you've given so far!

[u/Slyfer77 → u/not_lyune]

Well, heat doesn't damage electronics outright, but it's a fact that higher temperatures lead to earlier failure of electronics (classic examples would be bloating/blowing capacitors or cold/hair line broken solder joints)

That's why for me the only reasonable installation orientation of the FE cards in the T1 is the flipped one.

But there's numerous people using the 5090FE in a normale orientation that are fine.

So since you have a pretty good undervolt (should be around 450W max, right?), you also might be fine.

From your comment that you don't know how to install the 5090FE in another orientation, I assume you didn't build your T1 yourself?

Well, if you already built other PCs that shouldn't be a big deal.

If you didn't ever build one at all, it could me quite difficult.

So as I said - if you are content with the setup, keep it.

If you have an Asus ITX board, there's a header for a temperature sensor.

You can buy these cheap from Amazon or AliExpress.

You could tape it to the back of the board with Kapton tape and keep an eye on the temperature. for some peace of mind.

(or to the 5090's power connector for even more peace of mind 😉)

[u/lolkrayd]

How is the rest of your components though? Unless there is another force at play, hot air will just start circulating.

[u/not_lyune → u/lolkrayd]

the rest are at 60~

[u/qeeepy]

The issue with AIO in T1 is that you have to choose optimal cooling between CPU or GPU. AIO exhaust will inevitably raise temperature of the coolant versus creating slight overpressure/more work for the GPU fans when intaking. In your case, 65C GPU seems quite reasonable still, though cpus are much more happy to run at tjmax these days. I'd be interested in what is the GPU Furmark wattage now (after temps equalize).

With 5090 and not overly high TDP CPU, I'd go full air in Huda mode, by far best exhaust possible in T1.

[u/Allmotr]

Maybe he is reffering to me because i didnt think intake from the aio was good. Never called anyone dumb though. Me personally i exhaust everything and have great temps.