Understanding fan curves

[mergen3107]

Rules

• I made myself familiar with the Readme, FAQ and Troubleshooting.
• I understand that, if insufficient information or no app logs will be provided, my issue will be closed without an answer.

What's wrong?

Hi @seerge

Thank you very much for continuous support of G-Helper!
I am trying to understand if the behavior of fan control I have now is expected or there is a bug.

In short, it seems like fan speed will land on a slightly different value than what fan curve asks. See screenshot below:

At the current temperature, fans speeds are asked to be 10%. In reality, the G-Helper main window shows they are around 40% instead.

If I ask 90%, I get 100%.
If I ask 70% as on the screenshot, I get around 80%.

If this is a consistent offset, I am OK with this and I can just keep setting fan curves accordingly.

Please let me know if I can help you more, in case this is a bug.

How to reproduce the bug?

1. Setup fan curves as shown above
2. Observe G-Helper main window

Logs

log.txt

Device and Model

Asus Zephyrus GA403WR-XS97

Additional information.

No response

Armoury Crate

Uninstalled

Asus Services

0

Version

0.216.0

OS

Windows 11 24H2

[seerge]

@mergen3107 hello,

This is rather question to Asus and how firmware (that handles fans) interprets fan curves :)

Under the hood custom fan curves i.e. what you can set in Manual mode of Armoury or in G-Helper are set in some abstract % values.

Because from firmware standpoint:

• 0% means fans are OFF
• 1% is immediately something like ~2000RPM (depending on the model)
• 10% would be something like ~2200RPM and so on
• 100% is maximum possible sustained(!) fan speed. Which is ~6800RPM(?) for your G14.

At the same time fan speed reading from firmware is in actual RPMs (not %).

When you select fan speed reporting in %, G-Helper just calculates reported fan speed / maximum observed fan speed to get you a % value. That's why when you set fan speed to 10% - it would result into ~ 2200RPM, or 2200/6800 = 32% :) So here you see honest %.

I have explicitly decided to keep Y-axis on the chart in this "asus" %, cause it was asked by other users, who just want to copy their Armoury curves one to one. As both apps do here same thing after all.

You can also click on both Y-Axis on the chart and on Fan speed label to toggle between % and RPM reporting.

Y-axis with RPM is more accurate. Here it starts with OFF, but then from first grid-line it shows assumed RPMs like 2200, ending with maximal observed RPM on the top.

---

Additionally everything explained above - firmware still interprets custom fan curve only as a guideline usually. It has quite high hysteresis (i.e. a time delay) before reacting on temp changes. So fans won't jump to desired speed immediately. It also can decide to run fans faster if it believes device is too hot, etc.

That's absolutely normal. So don't expect it to follow your settings dot-by-dot.

---

There is also an Experimental build with a manual fan control that uses a separate driver (same one as MyASUS uses to run fan-testing). There it literally tries to set fan speeds manually. But I would advice to use it only if you are unhappy with default firmware performance and want to overcome it by some reasons.

I'm moving this to discussions as this is not an "issue" with the app, but rather a question.

Thanks

[mergen3107]

0% means fans are OFF
1% is immediately something like ~2000RPM (depending on the model)

Thank you! This explanation actually helps a lot :D Maybe it should be in a tooltip somewhere?

You can also click on both Y-Axis on the chart and on Fan speed label to toggle between % and RPM reporting.

Yep! I found this in the FAQ.

I just noticed a few things (sorry, I hope you don't mind leaving my thoughts here for future users):

• max RPM is different for CPU and GPU, being 7000 and 6800, respectively;
• They seem to have slightly different "accuracy". CPU fan speed is reported currently as 2500 RPM, GPU fans speed is reported as 2800 RPM, while both of them were "set" at 2200 RPM (by the fan curve).
• Precision while looking at the percentage values is deceivingly fine, the smallest delta is 1%. In RPM, the smallest delta shown is 200 RPM, which is around 3%, but I was able to adjust it so the reported value is sensitive to every 100 RPM. Now my two fans are matched at the reported 2500 RPM:

firmware still interprets custom fan curve only as a guideline usually. It has quite high hysteresis (i.e. a time delay) before reacting on temp changes.

Yes, I noticed it takes about 7-10 seconds to actually start ramping up, and then it takes its sweet time to reach required speed. Crazy! Sounds like a planned move to let chips cook more while it ramps up... Coming from a DIY desktop system, where the BIOS allows to setup response time of fan ramping as low as 0.1 seconds.

It also can decide to run fans faster if it believes device is too hot, etc.

Yes, of course, this is the result of the above. By the time fans reach RPM that matches X degrees, chips are already at Y > X degrees :D

There it literally tries to set fan speeds manually. But I would advice to use it only if you are unhappy with default firmware performance and want to overcome it by some reasons.

I saw that too. I think I am OK for now, as long as I understand more or less how it behaves, and your explanations cleared up a lot!

I will be testing G-Helper more and open a few more Discussions (mostly) and FRs. Let me know if there are specific tests you would me to perform on this new machine.

Thank you!

[mergen3107]

One more question please, before I forget.
Are the reported RPM values accessible by other programs? For example, currently I cannot see them in hwinfo.
I was trying to understand what max RPMs they reach during high loads, but as soon as I Alt-Tab to G-Helper, fans drops their speeds. My other options are running games windowed or maybe using a second monitor.

[mergen3107]

Also, sometimes when I switch between RPM/%, the points jump so that first n points are no at lowest 20 degC and all vertical. I don't know how to reproduce it consistently, but here are rough trial-and-error steps:

• from the screenshots above, for example, drag the third from the left points closer in X-axis to the second point, and slightly higher
• hit RPM/% axis to change it
• see the second and third points jump above the very first one. It seems like their Y-axis stays the same as they were at before, but X-axis drops to the minimum one (or maybe it tries to go to "0", but because of the tied logic, any next point cannot go beyond any previous point.

[seerge]

@mergen3107

max RPM is different for CPU and GPU, being 7000 and 6800, respectively;

Yes, and for possible 3rd fan if it exists - it's usually even higher. G-Helper remembers max RPMs for each fan independently

They seem to have slightly different "accuracy". CPU fan speed is reported currently as 2500 RPM, GPU fans speed is reported as 2800 RPM, while both of them were "set" at 2200 RPM (by the fan curve).

Because first step (i.e. 1%) on Y-axis always starts from 1800RPM, and ends with max RPM. Rest are calculated linearly between them and rounded to nearest 200RPM.

g-helper/app/Fans.cs

Line 717 in 649eeb5

return (200 * Math.Floor((float)(Min * 100 + (Max - Min) * percentage) / 200)).ToString() + unit;

While in reality - it's still up to firmware and may be slightly different.

Precision while looking at the percentage values is deceivingly fine, the smallest delta is 1%. In RPM, the smallest delta shown is 200 RPM, which is around 3%, but I was able to adjust it so the reported value is sensitive to every 100 RPM.

My main point here - just don't expect to match super accurately. Furthermore fan speed readings are also quite approximate due to the sensors themselves. I have seen 2 laptops of the same model report different maximum fan speed for example (while on firmware level it's clearly the same).

Are the reported RPM values accessible by other programs? For example, currently I cannot see them in hwinfo.

Yes, HWinfo can read them too (from same endpoint in asus driver as G-Helper does). It's just listed in a separate section in HWinfo

[mergen3107]

It's just listed in a separate section in HWinfo

Could you please shown me where? I can't find it. I also tried enabling "Show all fans" option

[seerge]

@mergen3107 actually, they seem to remove it now. But I'm 100% sure it was there before.

Could be due to asus changing required permissions in their recent Asus System Control Interface.

You can get them via powershell command by querying endpoint directly still tho

CPU

((Get-CimInstance -Namespace root/wmi -ClassName AsusAtkWmi_WMNB | Invoke-CimMethod -MethodName DSTS -Arguments @{Device_ID=0x00110013}).device_status -band 0xFFFF)

GPU

((Get-CimInstance -Namespace root/wmi -ClassName AsusAtkWmi_WMNB | Invoke-CimMethod -MethodName DSTS -Arguments @{Device_ID=0x00110014}).device_status -band 0xFFFF)

Multiply result on 100 :)