20°C improvements on GPU when swapping fans from 120mm to 140mm

[CapitainObvious]

Hey guys,

 

I'm wondering if it is normal to get a 20°C improvements on GPU when swapping front fans from 120mm to 140mm ?

 

To explain I just upgraded my build from a 3800X-2070 Super combo to a 7800X3D-7900XTX combo. I bought and started  playing Cyberpunk maxed out with my new system and my 7900XTX (Saphire nitro+) was like a jet engine and was really loud and in Adrenaline was showing 90°C temps under 100% load in Cyberpunk. Thought it was normal, annoying none the less, but I attributed it to being used to my 2070 Super which of course consumed way less power and everything. For information I did not do any kind of fan curve tuning and juste enabled Asus PBO in the BIOS but didn't touch anything fan related...

Today after a week I saw that I had two 140mm noctua (https://www.amazon.ca/-/fr/chromax-Black-swap-ventilateur-silencieux-qualité-supérieure/dp/B07654B9MR/) fans laying around and thought that I would replace my dual 120mm front noctua (https://www.amazon.ca/-/fr/NF-A12x25-chromax-Black-swap-ventilateur-silencieux-supérieure/dp/B09C6DQDNT/) fans because it can't hurt. My case is a NZXT H510 Flow.

After changing the front fans, when playing Cyberpunk, I get the same FPS but the 7900XTX is really quiet and temps in Adrenaline shows 70°. The improvements are incredible and honestly a life changer in terms of noise (no more jet engines!) and of course temps: -20° is incredible.

The thing is it seems too good to be true, and I don't really know if it's the fans or something else... Do you guys think it's the fans because the 120mm fans where a model that did not provide enough airflow and that combined with a bigger, more able 140mm fans did the trick? Maybe it's auto tuning by asus or amd software that was like learning and dialed everything right by coincidence just after changing the front fans? Of course I gladly take the win, just really curious about the how and why to learn!

[Godlygamer23]

When you changed the fans, I assume you reapplied the thermal paste too, correct?

[thrasher_565]

so let me guess you had 120m fans with the old build and did an new build and added 140mm fans and you think its the fans?

 

my guess is if there ant preforamce it be like 1c ish...

 

could the new pc use better on temps ya thats posable.

Edited February 10 by thrasher_565

[CapitainObvious]

3 hours ago, Godlygamer23 said:

When you changed the fans, I assume you reapplied the thermal paste too, correct?

No I changed thermal paste when I changed the CPU so before installing the 7900XTX. The only thing I did between those temps is really change the front fans of the case.

[CapitainObvious]

2 hours ago, thrasher_565 said:

so let me guess you had 120m fans with the old build and did an new build and added 140mm fans and you think its the fans?

 

my guess is if there ant preforamce it be like 1c ish...

 

could the new pc use better on temps ya thats posable.

No not at all, I may have not expressed my self in the best way.

I upgraded my PC with new CPU, RAM, GPU and motherboard and kept my old 120mm front fans. With all that my new GPU (the 7900XTX) was hitting 90 degrees in Cyberpunk. Then 1 week latter I changed the front fans, I literally just did that, and I see 70 degrees on the new gpu (the 7900XTX) in Cyberpunk witht he exact same settings and windows install.

 

It seems really weird to me too and I don't really understand what could have happened, that's why I'm posting here.

[Godlygamer23]

14 minutes ago, CapitainObvious said:

No I changed thermal paste when I changed the CPU so before installing the 7900XTX. The only thing I did between those temps is really change the front fans of the case.

What profiles existed on the fans prior to upgrading fans?

[thrasher_565]

35 minutes ago, CapitainObvious said:

No not at all, I may have not expressed my self in the best way.

I upgraded my PC with new CPU, RAM, GPU and motherboard and kept my old 120mm front fans. With all that my new GPU (the 7900XTX) was hitting 90 degrees in Cyberpunk. Then 1 week latter I changed the front fans, I literally just did that, and I see 70 degrees on the new gpu (the 7900XTX) in Cyberpunk witht he exact same settings and windows install.

 

It seems really weird to me too and I don't really understand what could have happened, that's why I'm posting here.

20c different from fans is not a thing like ever... cheap fans to like really good fans is like 5c. so something is not adding up.

even if you went from 800 rpm to like 3000 rpm fans you wont see a 20c drop... so...

Edited February 10 by thrasher_565

[Ralfi]

I was going to suggest you change back to the 120mm fans & then back to the 140mm to see what happens.

 

But on second thought, it’s probably best to not touch this PC ever again  

[RevGAM]

If the only thing you changed was the fans, then the fans caused the change. It cannot be anything else.

 

How can this be? Well, you've changed not just the fans, but where the air is flowing to. This is because the 140s have a different radius, so the wind, which was previously not feeding the right area(s) is now doing so. If you ran a smoke test, you would see the difference in flow. Am I surprised by how big the difference is? Absolutely.

 

Another difference is that, despite the fact that the NF-A15-HS has a max 1500 RPM, vs 2000 RPM for the NF-A12x25, it's still going to push more air and be quieter at max.

 

That's my impression, at least.

 

The only other thing I can think of is that the new TIM needs time to "cure" before it produces optimal results, like phase-change materials (e.g. Honeywell PTM7950), and those that have to be "burned in" with repeated high-temperature.

[CapitainObvious]

Hey guys, for anyone interested in a follow up, I found the issue! It seems that after a full reboot when changing the fans the graphics cards applied the correct (default?) fan curves!
I didn't change anything but it appears that the fan curves applied the first time where super agressive and after a reboot when installing the new fans, for whatever reason the graphic cards applied correct way more moderate fan curves.
So yeah it had nothing to do with the front fans being swapped just a coincidence, but thanks everyone for the tips and the explanations!

[TatamiMatt]

13 hours ago, CapitainObvious said:

Hey guys, for anyone interested in a follow up, I found the issue! It seems that after a full reboot when changing the fans the graphics cards applied the correct (default?) fan curves!
I didn't change anything but it appears that the fan curves applied the first time where super agressive and after a reboot when installing the new fans, for whatever reason the graphic cards applied correct way more moderate fan curves.
So yeah it had nothing to do with the front fans being swapped just a coincidence, but thanks everyone for the tips and the explanations!

The less aggressive fan curve changing noise i get but this just means a drop of 20C occurred with less fan speed, only thing i can think of is the 120mm fans were not pushing almost any air to begin with and the gpu was circulating its own hot air? the 140mm changed where the air was flowing and how much air was flowing and stopped this circulation pattern

[thrasher_565]

On 3/7/2024 at 11:21 AM, CapitainObvious said:

Hey guys, for anyone interested in a follow up, I found the issue! It seems that after a full reboot when changing the fans the graphics cards applied the correct (default?) fan curves!
I didn't change anything but it appears that the fan curves applied the first time where super agressive and after a reboot when installing the new fans, for whatever reason the graphic cards applied correct way more moderate fan curves.
So yeah it had nothing to do with the front fans being swapped just a coincidence, but thanks everyone for the tips and the explanations!

ya see there no way in heck you get a 20c drop from swapping fans even to server fans... even taking the pc out of the case...

but its good we found the problem.

if you want 20c drop your water cooling or lm...

Edited March 9 by thrasher_565

[RevGAM]

On 3/8/2024 at 4:14 AM, TatamiMatt said:

The less aggressive fan curve changing noise i get but this just means a drop of 20C occurred with less fan speed, only thing i can think of is the 120mm fans were not pushing almost any air to begin with and the gpu was circulating its own hot air? the 140mm changed where the air was flowing and how much air was flowing and stopped this circulation pattern

Whatever it was, there was probably a disruption in airflow because of the previous configuration.