ASUS Zephyrus GA401I Severe Lag, Suspect Motherboard/Power Issue - Need Help Diagnosing

[MakNCheese]

Hi everyone,

I'm having a serious issue with my ASUS Zephyrus GA401I (4 years old, worked perfectly until recently). The system is lagging heavily, even in the BIOS, and is charging extremely slowly (a few percent in hours), making it nearly unusable. I suspect a motherboard or power delivery issue.

Symptoms:

• Severe lag across the system, including BIOS navigation.
• Slow boot times and unresponsive performance in Windows.
• Battery charges very slowly (e.g., ~5% in 2–3 hours).
• No error messages or BSODs, just extreme sluggishness.

What I've Tried:

• Replaced the charger – no improvement in lag or charging speed.
• Replaced the battery – no change in symptoms.
• Tested running on adapter only (no battery) – same lag issue.
• Verified charger pin voltage – it's good.
• Reformatted the system (clean Windows install) – no effect.
• Tested RAM with MemTest86 – no errors detected.
• Visually inspected the motherboard – no obvious signs of damage (e.g., burnt components, bulging caps), but I'm not an expert.

[Sephir0th]

Charging controller is a BQ24780S? If yes, resistances between ACN and ACP pins at the controller?

[MakNCheese]

Charging controller is a BQ24780S? If yes, resistances between ACN and ACP pins at the controller?

I am not at home right now. Give me some time then I will try this. This has to be done with the laptop not plugged in, right?

[Sephir0th]

I am not at home right now. Give me some time then I will try this. This has to be done with the laptop not plugged in, right?

Correct, no power at all

[mcplslg123]

Another thing to look for is PROCHOT#

[MakNCheese]

Charging controller is a BQ24780S? If yes, resistances between ACN and ACP pins at the controller?

Yes, it is BQ24780S. I tried this using my multiple probes, but they are not thin enough. So, couldn't get a perfect reading. One time it was 80 ohms, and the next time, I tried it was 4.60 k ohms. I have ordered new fine probes and will get readings again

[MakNCheese]

Another thing to look for is PROCHOT#

Thanks for the response. Could you please let me know how to do that?

[Sephir0th]

Yes, it is BQ24780S. I tried this using my multiple probes, but they are not thin enough. So, couldn't get a perfect reading. One time it was 80 ohms, and the next time, I tried it was 4.60 k ohms. I have ordered new fine probes and will get readings again

Share a picture of the charging controller and surrounding circuit please. We will find suitable measurement points.

[m1ch43lzm]

Ryzen CPU? You can download HWINFO64
https://www.hwinfo.com/download/
Get the portable version, open it and select "Sensors only"
Then scroll down until you get something like this


If it shows PROCHOT_EXT as "yes", that's the issue
Another thing to look for is the CPU will be stuck at 400MHz
It happened to me on a HP laptop, could be anything like a bad pull-up resistor on that line, to an IC pulling down the line for whatever reason

[MakNCheese]

Ryzen CPU? You can download HWINFO64
https://www.hwinfo.com/download/
Get the portable version, open it and select "Sensors only"
Then scroll down until you get something like this


If it shows PROCHOT_EXT as "yes", that's the issue
Another thing to look for is the CPU will be stuck at 400MHz
It happened to me on a HP laptop, could be anything like a bad pull-up resistor on that line, to an IC pulling down the line for whatever reason

Do you think that PROCHOT could be the reason? I'm asking because the battery is also not charging properly and very slowly. If prochot is the issue, the battery should charge at normal speed when the pc is off?
I formatted the SSD but couldn't install Windows on it because of system running very slow to check prochot I will have to install another SSD on it.

[m1ch43lzm]

Schematics for the GA401IH, may be close https://www.badcaps.net/forum/troubl...-ga401iv-br9n6

From the schematics the charger IC PU8900 has a connection to PROCHOT#, and there's a circuit for HW throttle on the same page that also goes to PROCHOT#, so yes, it may be related to a fault in the charge circuit
SN2867 = BQ24780S

[MakNCheese]

Share a picture of the charging controller and surrounding circuit please. We will find suitable measurement points.

I measured the resistance between pins ACN and ACP pins it was 0 ohms. Though I am still not sure of the readings. I am attaching pictures of the motherboard and the schematics is attached above.

[Sephir0th]

I measured the resistance between pins ACN and ACP pins it was 0 ohms. Though I am still not sure of the readings. I am attaching pictures of the motherboard and the schematics is attached above.

Closer and better quality please

[MakNCheese]

Closer and better quality please

Will these work?

[MakNCheese]

Closer and better quality please

Do you see anything that might be causing an issue? It's sunday and I can spend a lot of time on this. Appreciate your help

[Sephir0th]

Will these work?

It's just needs to be visualized what connects to where. So instead of to measuring between ACN and ACP directly you can measure between these two points.

[MakNCheese]

It's just needs to be visualized what connects to where. So instead of to measuring between ACN and ACP directly you can measure between these two points.

Thanks mate. Checked these points and ACP and ACN points directly. The resistance between the two comes out to be 0. Continuity is there too

[Sephir0th]

Okay, let's check voltage of PROCHOT# then. Unfortunately this becomes more complicated since there is no nearby component where we can measure. So either you move carefully and with thin probes to Pin 10 directly or you carefully scrape the mask of the via to make this track better accessible.

The important part here is a) to perform this test with the board powered AND turned on and b) to not slip with the probes...