Need help reaching Package C8 on Intel N100

[tmkhiem]

Hi! I just bought a N100 laptop and performed a clean Windows 10 Installation on it. Since I will be using the machine for on the go working, after installing all drivers, I proceed to download ThrottleStop to optimize the battery usage. However, I'm at my wit's end because I have tried everything that I know (there is a list of them below) but no matter what I do, I cannot achieve package states deeper than C3.

Laptop's specification:

• Manufacturer: CHUWI
• Intel N100 Alder Lake
• LPDDR5 16GB 4800MHz soldered on
• 512GB AirDisk SSD
• BIOS: AMI
• LAN NIC: Internal Realtek USB FE
• WLAN NIC: Intel AX101

As with most noname manufacturers out there, I got almost every setting imaginable available for tuning. Almost nothing is hidden away. I could configure FIVR in the BIOS but whether it is effective is an another story, however I could see that disabling CFG lock in BIOS did reflect in ThrottleStop (no more "C States Locked").

Software specification:

• Windows 10 Home 22H2
• ThrottleStop 9.6
• Timer resolution in "Options" 15.62, a "relaxed" value I believe.
• powercfg /energy returns no error and some minor warnings.

What I have tried:

• Disabling the Internal Realtek LAN NIC. I also have an another laptop (i7-8550U) that only reaches PC8 with latest Realtek drivers. I tried updating the Internal NIC but it didn't work this time. Also

  powercfg /energy

  reported that it cannot do selective suspend and with it being a 100M only NIC I disabled the USB port altogether.
• Updating the Microsoft AHCI driver to "Intel 500 Series chipset AHCI controller". I have read somewhere that MS default AHCI drivers will prevent the system from going deeper than PC3 but still no luck. I know that Alder Lake would be equivalent to 600 series chipset but I can't find the AHCI drivers for 600 series anywhere.
• Followed this post on modifying relevant BIOS settings. I don't need to use the mentioned tool (AMISCE) because they're all available . But didn't work.
• Manually forcing DMI ASPM, SA PCIE ASPM and PCH PCIE ASPM to Auto, L1 and L0sL1. Both without success. I'm leaving it at L1.
• Manually entering C6/C7, C8, C9 and C10 Latency values that I copied from another system. My theory is that it's possible that a zero value may have somehow disabled the C state. It seems not to be the case, though.
• Enabled S0i2.0 and S0i3.0 -- no changes. From what I gather, they are supposed to be the "new sleeping" standard in place of S3 so I figured they might have something to do with low power.
• Turning on Speed Shift + EPP since it is disabled the first time I open ThrottleStop. I'm not sure if this matters with AlderLake.

What's weird:

• Apparently, there could be some BIOS settings that will render other settings ineffective (i.e. will be of no function without being grayed out). I tried limiting maximum Package C State to C2 and C1 but both ThrottleStop and HWINFO still shows some PC3 residency. However, some other tinkering around results in PC3 and PC2 not getting any altogether so I thought my current BIOS setting is as good as I can get.
• Right now both core C6 and C7 are at over 90%. I don't think this is possible because I think the sum of one core's C3%, C6% and C7% should not exceed 100% (Did I understand it right?). This is verified with MSR reading at 0x000003FD (CC6) of 00000020:2D553138 and reading at 0x000003FE (CC7) of 0000001F:5AE1F26F, while 0x000003F9 (PC6), 0x000003fa (PC7) and deeper states return all zeros.
• "C-State auto demotion" and "C-State undemotion" has only two possible values: Disabled and C1. Selecting C1 results in ThrottleStop showing "C1" button instead of "C9" but inside ThrottleStop's C States window still shows C9.
• In some combination of BIOS settings (I did not do a great job at keeping track of which settings has what value partly due to the vast amount of settings), requesting C7 will prevent Package C3 but allows Package C2.
• In some other combinations, like what I'm having currently, requesting C1 does not have any effect at all. The package still reaches C3.

Attached are some screenshots of ThrottleStop. Due to the vast amount of configurable settings in the BIOS I could not show them all here, and some of them have been changed, but any help would be appreciated!

EDIT: Added some logs.

 

[unclewebb]

both core C6 and C7 are at over 90%. I don't think this is possible

I agree. On most Intel CPUs, the sum of the individual core C states as reported in ThrottleStop does not exceed 100%. The values in the C6% column of the ThrottleStop C state monitoring table are all higher than the C7% column. Whatever is being reported in the C6% column might be multiple different C states including C7%. I have never owned or had access to an Intel N100 CPU for testing purposes. How well ThrottleStop works on the N100 is unknown. There might be bugs like the C state bug you found.

On my 10th Gen desktop CPU, I have never made it beyond package C3. It might be a driver that blocks the deeper package C states. I gave up trying to figure out why. On a desktop CPU, a tiny amount of idle power is not worth chasing after. Hopefully you can find a way to unlock the package C state mystery. Lots of laptop owners could use some extra battery run time.

 

[mkdr]

I just got a Chuwi Herobox 2023 with Intel N100 (same configuration as your Chuwi laptop it seems, same ram, same Intel AX101) and set it up the last hours. The included fan is really annoying. But I had high hopes that I could just tweak the device, so I could detach the fan and make it run fanless. Which I actually just achieved. I limited PL1 and PL2 to 8W, and now the device runs fanless (I just opened it and detached the fan cable) between 70°C to 82°C.

The only thing so far though: I am not able to make the package enter any C state higher than C3 it seems. I found this post, and I get same results in ThrottleStop for the N100. Around 2.5W idle package but TS shows for package highest C state is C3 and for cores C7.

Wondering if the N100 cant go lower for package than C3? Or if this is some configuration issue. I tried to look into the bios, but all looks normal to me, couldnt find any settings so far where C states were disabled.

My Dell XPS 15 9570 with 8th gen 8750h CPU, it enters C8 for package (C10 only but only when I remove the power cord and it runs on battery) and can go low as 0.6W, with modern standby it enters C10 (I notice there is kinda no difference in power draw anymore it seems between C8 and C10). I am sure the N100 could do the same, the 2W for idle difference is actually a lot. Wonder if it is some stupid Windows or driver issue. I tried both power profiles with no luck, balanced and energy saving, no difference.

Update: After some more testing, when I enable modern standby, aka "Low Power S0 Idle Capability" in Chuwi bios to enabled, I get C10 state shown in TS, but only, when I put the box to sleep / modern standby. Under normal running condition, I still dont get lower than C3 for package and around 2.4W.

 

[tmkhiem]

Does your system also show the CC6 and CC7 values over 90% simultaneously? I think there is something wrong (possibly a bug unrelated to ThrottleStop but maybe msr/microcode?) here.

 

[mkdr]

@tmkhiem yes indeed, it shows the exact same values as yours. so that might be a bug actually showing both C6 and C7 kinda the same values for core, or there is some weird definitin how C7 is counted that it also counts C6 with it. but the state for package must be correct, because that is kinda the same value I also get for my 8th gen 8750h when it wont enter C8 and just C3 for package, it would be idle between 2-3w and when it can go down to C8 or C10, package goes to around 0.5w. so thats kinda 2w of waste for idle which is a lot.

I went through bios again and tried a few things nothing worked. I also updated the Realtek GBit Adapter driver to latest from Realtek page for the one which includes power saving, also didnt help. wonder if some of the countless drivers maybe preventing it, like bluetooth, usb, or some of the Intel drivers. I tried to disable the AX101 which didnt help, also removed all USB cables I had on the box. no luck so far. might also be a bios issue of the Chuwi devices which all share the same bios.

I have tried to look if I see anywhere a screenshot posted by anyone on the web from a N100 in TS, proofing that it can indeed enter C8 and go down to 0.5w for package, not found one so far. might also be some combination of the iGPU maybe from the N100.

for your laptop, did you update the Intel GPU drivers, did you check in the Intel GPU tool, the old one, not the new purple tool, under display, if you have a display power save option? I remember I had this issue on my Dell XPS before, that if you dont enable it, it also wont enter pkg C8.