Question System Fans - CPU Cooling

Aug 28, 2020
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1
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Hi!

So, my system temps are okay, but it's maybe too loud sometimes.

The question is, should the system fans look at CPU or SYSTEM temperature when setting their speed?
Now when my Ryzen 7 2700x temp is jumping 43 --> 51 --> 43 fast, the system fans are doing the same thing at their speed, but i think in that way i can keep the temps okay. 🤔


CPU (Ryzen 7 2700x)
Idle: ~42°C
Gaming: ~53-60°C


GPU (ASUS Geforce RTX 2070S)
Idle: ~34°C
Gaming: ~50°C


System
Idle: ~30°C
Gaming: ~32°C
 

Barty1884

Titan
Moderator
Typically, MB connected fans look to CPU temperature. Very few offer the configuration to ramp up/down against anything other than CPU temp.

Some GPUs have fan headers on them, so you can have case fans coincide with GPU (core?) temps.
 

madmatt30

Titan
Ambassador
Hi!

So, my system temps are okay, but it's maybe too loud sometimes.

The question is, should the system fans look at CPU or SYSTEM temperature when setting their speed?
Now when my Ryzen 7 2700x temp is jumping 43 --> 51 --> 43 fast, the system fans are doing the same thing at their speed, but i think in that way i can keep the temps okay. 🤔


CPU (Ryzen 7 2700x)
Idle: ~42°C
Gaming: ~53-60°C


GPU (ASUS Geforce RTX 2070S)
Idle: ~34°C
Gaming: ~50°C


System
Idle: ~30°C
Gaming: ~32°C
If you're using the stock ryzen cooler with its 2000+ rpm fan and you're using 120/140mm case fans it's a bad idea imo setting them to coincide with the cpu cooler.
Itll run them full pelt most of the time.

What board is it?
And case/fan configuration?
Most boards allow custom fan curves or a multitude of variable fan modes.

Typically, MB connected fans look to CPU temperature. Very few offer the configuration to ramp up/down against anything other than CPU temp.

Some GPUs have fan headers on them, so you can have case fans coincide with GPU (core?) temps.
I dunno about that, asrock pro 4 let's you set off motherboard temps as well as cpu temps.
Also has silent and aggressive manual modes available.
 

Barty1884

Titan
Moderator
I dunno about that, asrock pro 4 let's you set off motherboard temps as well as cpu temps.
Also has silent and aggressive manual modes available.
That's where "typically" and "very few" came into it.;)
Admittedly, I haven't used an ASRock board in a long time,so that's good to know.

There was a board..... from Gigabyte I believe it was, that could have fans coincide with "VRM Temp" or something like that. Yet there was no thermocouple for accurate temp readings.... Was taking the same source you can get in software, sits somewhere between an educated deduction & a complete shot in the dark.
 

madmatt30

Titan
Ambassador
That's where "typically" and "very few" came into it.;)
Admittedly, I haven't used an ASRock board in a long time,so that's good to know.

There was a board..... from Gigabyte I believe it was, that could have fans coincide with "VRM Temp" or something like that. Yet there was no thermocouple for accurate temp readings.... Was taking the same source you can get in software, sits somewhere between an educated deduction & a complete shot in the dark.
Am3+ gigabyte boards did that.

To be honest I keep my 140mm intakes at a set 800rpm and only allow the exhaust to be variable.

Depends on the case model and fan configuration, I don't think there's any need whatsoever for variable speed on intake fans personally.
 

Barty1884

Titan
Moderator
To be honest I keep my 140mm intakes at a set 800rpm and only allow the exhaust to be variable.

Depends on the case model and fan configuration, I don't think there's any need whatsoever for variable speed on intake fans personally.
I agree. With a case with good ventilation (and decent fans), a static 800-1000rpm is probably plenty.

With a choked off case though, I could see the need for variable. You don't need them going full bore all the time for light workloads etc. But intensive tasks, they'd need to ramp up pretty quick;y.
 
Jul 28, 2020
3
0
10
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Hi!

So, my system temps are okay, but it's maybe too loud sometimes.

The question is, should the system fans look at CPU or SYSTEM temperature when setting their speed?
Now when my Ryzen 7 2700x temp is jumping 43 --> 51 --> 43 fast, the system fans are doing the same thing at their speed, but i think in that way i can keep the temps okay. 🤔


CPU (Ryzen 7 2700x)
Idle: ~42°C
Gaming: ~53-60°C


GPU (ASUS Geforce RTX 2070S)
Idle: ~34°C
Gaming: ~50°C


System
Idle: ~30°C
Gaming: ~32°C
some mother boards will let you assign a fan header to something specific to monitor. My Gigabyte X570 has 7 fan headers and each can use CPU, system and I believe one other item as the tracking item. I set them all to CPU temp since CPU is what will thoroughly off so much heat under load and you want to get that heat out of the case as quickly as possible otherwise the ambient temps in the case will climb causing CPU temps to,rise. Ideally you are moving enough air so that as heat is given off by CPU, VRM, etc. is removed from the case as quickly as it is generated. Once you do that it comes down to how effectively the HSF is at removing heat from the CPU And that will determine Max CPU temps. If you do all that and stay under the thermal throttling limits of the CPU then you get all the performance you paid for.

I set CPU fans to run 100% all the time and then case fans run around 50% until CPU gets up over 70C then they ramp up to make sure the CPU gets all the air it needs to stay cool. I have 2 140mm intake, 2 140mm exhaust at top of aces and then a 120mm exhaust at back. I can probably lower the case fans and not ramp them up so high, but the CPU temps rarely get over 70C and then not for long.
 
Aug 28, 2020
12
1
15
0
If you're using the stock ryzen cooler with its 2000+ rpm fan and you're using 120/140mm case fans it's a bad idea imo setting them to coincide with the cpu cooler.
Itll run them full pelt most of the time.

What board is it?
And case/fan configuration?
Most boards allow custom fan curves or a multitude of variable fan modes.



I dunno about that, asrock pro 4 let's you set off motherboard temps as well as cpu temps.
Also has silent and aggressive manual modes available.
Yeah, Bitfenix Aurora with 2 140mm Noctua fans blowing inside on the front, one 120mm Noctua blowing outside from the back, one 140mm Noctua blowing out from the roof and one 120mm Arctic blowing out from the roof.

MSI B450 Gaming Pro Carbon AC

Now when i started thinking, maybe those system fans could be at 800-1000RPM all the time, not at smart mode, i think they can stay cool if the CPU is like 50+°C 🤔
 

madmatt30

Titan
Ambassador
Yeah, Bitfenix Aurora with 2 140mm Noctua fans blowing inside on the front, one 120mm Noctua blowing outside from the back, one 140mm Noctua blowing out from the roof and one 120mm Arctic blowing out from the roof.

MSI B450 Gaming Pro Carbon AC

Now when i started thinking, maybe those system fans could be at 800-1000RPM all the time, not at smart mode, i think they can stay cool if the CPU is like 50+°C 🤔
What cooler are you using on the cpu?

If its the stock cooler are you wcrtain it's not that making the noise rather than the case fans?

All the money you've spent on case fans would have been better spent on a decent cpu cooler in all honesty.

Also that configuration you have isn't optimal, you never want 2 roof exhaust fans with any air cooler on the cpu.


The top front one will be removing cool airflow from the front intakes before it ever reaches the cpu heatsink.
 
Aug 28, 2020
12
1
15
0
What cooler are you using on the cpu?

If its the stock cooler are you wcrtain it's not that making the noise rather than the case fans?

All the money you've spent on case fans would have been better spent on a decent cpu cooler in all honesty.

Also that configuration you have isn't optimal, you never want 2 roof exhaust fans with any air cooler on the cpu.


The top front one will be removing cool airflow from the front intakes before it ever reaches the cpu heatsink.
So if i flip the front top fan, is it better? Or what could be better? Maybe all the front and top flowing in?
 
Aug 28, 2020
12
1
15
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I removed the front top fan and now i'm installing Microsoft Flight Simulator

CPU before when i was installing: 50-52°C

CPU now when i am installing: 42-43°C
 

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