Hight CPU and battery usage on idle system; restarts don't help

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Shaamaan

Senior Member
Apr 30, 2010
188
4
I've got a problem with my S8 which is running latest, official, non-rooted XEO firmware. Specifically, it uses battery like crazy and heats up whilst doing nothing. This smells like a virus / malware infection or just... well, the last update was in December 2021 so it's also possible some system component is wonky OR... <shivers> some rootkit? I'm generally rather careful when installing apps, most of which will be coming in from official sources (Google Store) or at least fairly trusted sources.

Every so often I'll get a warning that a system component is using too much CPU and I should restart the phone - which obviously doesn't help at all. Also the battery drain is reported primarily by Android System and System Core (29 and 15% respectively). Battery usage stats generally don't add up because the listings don't add up to 100%. :/

I know the S8 is an old phone... and I know there are probably steps I should take prior to asking here - like a factory reset. But I'm really sceptical of doing a factory reset simply because I've got so much stuff on the phone that, while not impossible to backup, is certainly annoying (authenticator or banking apps for example - and I don't think the standard backup tools like those available from Google or Samsung backup such apps).

So I'd rather try some solutions or methods of dealing with the damned thing without resetting the phone first. Is there anything I can do?
 
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blackhawk

Senior Member
Jun 23, 2020
10,430
4,145
Samsung Galaxy Note 10+
You need to find the root cause. It may be a 3rd party using one or more of the Samsung system apps running under Android services, lol Legend for there are many... all lumped together.
A firewall with logging can help. Karma Firewall is what I use, uses almost no battery. Being rooted you have more options... use them.
Malware is always a possibility.

3rd party apps can cause hell. I don't allow any social media apps on the phone, ever.
Try in safe mode... if things calm down it's likely a 3rd party app. If so start going through the installed apps.
Clear system cache.
 
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Shaamaan

Senior Member
Apr 30, 2010
188
4
You need to find the root cause. It may be a 3rd party using one or more of the Samsung system apps running under Android services, lol Legend for there are many... all lumped together.
A firewall with logging can help. Karma Firewall is what I use, uses almost no battery.
Will try that, thanks!
Being rooted you have more options... use them.
The phone is NON-rooted. :(
Malware is always a possibility.

3rd party apps can cause hell. I don't allow any social media apps on the phone, ever.
Try in safe mode... if things calm down it's likely a 3rd party app. If so start going through the installed apps.
Clear system cache.
Oh, safe mode! I'll try that too! Thanks!
 
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blackhawk

Senior Member
Jun 23, 2020
10,430
4,145
Samsung Galaxy Note 10+
Will try that, thanks!

The phone is NON-rooted. :(

Oh, safe mode! I'll try that too! Thanks!
Sorry about the root thing, my bad.
If you're running on Android 9 or lower Karma Firewall's logging feature is fully active otherwise not. Samsung store>Galaxy Labs> Battery Tracker can be useful.
I use Accubattery's history page to get a quick idea of charge/discharge rates.
I use Device Care>storage>clean as well.
Make sure no cloud apps are running in the background.
 

Shaamaan

Senior Member
Apr 30, 2010
188
4
Update: in safe mode the phone doesn't heat up and battery usage seems normal. So it's probably some app.

Alas, the firewall wasn't very helpful - it seemed that apps that attempted accessing the internet were your usual suspects - Play Store, One Drive or other sync apps, Vanced.

Any other suggestions on possibly nailing down the culprit?

PS. I've also decided to send Samsung an error report via the Members app - I don't know what their reply times are and I honestly don't expect much from them but who knows? Perhaps they'll come through. :p
 

blackhawk

Senior Member
Jun 23, 2020
10,430
4,145
Samsung Galaxy Note 10+
Update: in safe mode the phone doesn't heat up and battery usage seems normal. So it's probably some app.

Alas, the firewall wasn't very helpful - it seemed that apps that attempted accessing the internet were your usual suspects - Play Store, One Drive or other sync apps, Vanced.

Any other suggestions on possibly nailing down the culprit?

PS. I've also decided to send Samsung an error report via the Members app - I don't know what their reply times are and I honestly don't expect much from them but who knows? Perhaps they'll come through. :p
Why other than maybe text messages is anything syncing? Take out the trash and go from there.
The ones that are connecting every minute or more when not open are prime suspects.
Some apps like Brave browser need to be closed out when not in use or they eat battery.

You can also try a hard reboot.
 
Last edited:

Shaamaan

Senior Member
Apr 30, 2010
188
4
Update!

I left the phone in safe mode overnight. I mean, it seemed like things were better, so at least I'd have a stable phone.

Well, in the morning I was greeted with a severely depleted battery (went from 100 to 40 in the span of 6 hours) and I got the "high CPU usage" warning popup. The phone wasn't as hot to the touch tho.

So... Whatever is going on seems to happen also in safe mode, albeit less often? Or perhaps it's less "severe" where it doesn't heat up the phone but the drain is still there? But since safe mode is affected it's probably NOT an app, right?

At this point I'm completely baffled. Any other ideas?
 

blackhawk

Senior Member
Jun 23, 2020
10,430
4,145
Samsung Galaxy Note 10+
Update!

I left the phone in safe mode overnight. I mean, it seemed like things were better, so at least I'd have a stable phone.

Well, in the morning I was greeted with a severely depleted battery (went from 100 to 40 in the span of 6 hours) and I got the "high CPU usage" warning popup. The phone wasn't as hot to the touch tho.

So... Whatever is going on seems to happen also in safe mode, albeit less often? Or perhaps it's less "severe" where it doesn't heat up the phone but the drain is still there? But since safe mode is affected it's probably NOT an app, right?

At this point I'm completely baffled. Any other ideas?
Hard reset... hold power button until it powers off.
Try temporarily disabling Google play Services at night, see what that does.
 

Shaamaan

Senior Member
Apr 30, 2010
188
4
OK, I'm baffled. I feel like I didn't really do anything but the phone is now running fine. Battery drain now might be better than ever! 😮

Warms up on usage, obviously, but when idle it's nice and cool and battery drain seems minimal. I'll... leave it for a few days to see how this develops. It's very difficult to tell what the heck's the case here.
 
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blackhawk

Senior Member
Jun 23, 2020
10,430
4,145
Samsung Galaxy Note 10+
OK, I'm baffled. I feel like I didn't really do anything but the phone is now running fine. Battery drain now might be better than ever! 😮

Warms up on usage, obviously, but when idle it's nice and cool and battery drain seems minimal. I'll... leave it for a few days to see how this develops. It's very difficult to tell what the heck's the case here.
Retrace what you did. Reason being you may need to do it again. Really most times all you need to do is just "play" with it a bit (a lot🤣). Almost impossible to crash a stock load, so explore and learn by playing with it. You are what you load and download; be careful with 3rd party apps they are the biggest potential hazards.

Once you have a fast, stable OS that's fulfilling its mission, let it be. Don't update or upgrade it.
Updates can and do break Sammy's. This N10+ is still running on Pie, current load is over 2yo. Rock solid stable and it runs like a bat out of hell with minimal maintenance. Security isn't an issue.
 

Shaamaan

Senior Member
Apr 30, 2010
188
4
Retrace what you did. Reason being you may need to do it again. Really most times all you need to do is just "play" with it a bit (a lot🤣). Almost impossible to crash a stock load, so explore and learn by playing with it. You are what you load and download; be careful with 3rd party apps they are the biggest potential hazards.
I have a suspicion this might have been some Samsung app (my bet's on Bixby) since those are likely still able to run in Safe Mode that got updated and then fixed...? Does that make sense?
Once you have a fast, stable OS that's fulfilling its mission, let it be. Don't update or upgrade it.
Updates can and do break Sammy's. This N10+ is still running on Pie, current load is over 2yo. Rock solid stable and it runs like a bat out of hell with minimal maintenance. Security isn't an issue.
I'm concerned about the last bit. I mean, upgrading to a new Android version is one thing but security updates are common, no?
 

blackhawk

Senior Member
Jun 23, 2020
10,430
4,145
Samsung Galaxy Note 10+
I have a suspicion this might have been some Samsung app (my bet's on Bixby) since those are likely still able to run in Safe Mode that got updated and then fixed...? Does that make sense?

I'm concerned about the last bit. I mean, upgrading to a new Android version is one thing but security updates are common, no?
Kill wittle bixby... you read it EULA?☠
It's more than one apk though. Takes a while to optimize a Sammy the first time🤣

Well... if it's set up and used right Android 9 will run securely in the real world. No saving dumb bunnies anyway; they'll still get tagged even with the latest version🤣
The proof is in my hand. Loaded over 2+ years ago and this N10+ UI version 1.5 is running clean like a bat out of hell. If I do get malware I can't erraticate in an hour or so, factory reset and change passwords.
My data is redundantly backed* up 4+ times, plus the onboard SD card used as a data drive. I'm ready to reload right now if I have to...

A malware forced reload is still less trouble than constantly updating and having the updates screw things up. That means more troubleshooting, finding new work arounds and still maybe needing a factory reset on top of all that. No.
Not vaxed either... not buying the hype.


*critical data must be redundantly backed up or sooner or latter it will likely be lost. Never encrypt data drives as you are the most likely to be locked out!
 

Shaamaan

Senior Member
Apr 30, 2010
188
4
Kill wittle bixby... you read it EULA?☠
Oh I'd love that - but it's a system app and removing those without root is kind of... impossible? I can look into disabling it completely however - I never use it anyway. Since it's not a single app - any chance you got a link to the list of apps that need manual disabling?

Anyway, I'm still getting those damned warnings. :( The phone isn't constantly hot however, which is some improvement.
 
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blackhawk

Senior Member
Jun 23, 2020
10,430
4,145
Samsung Galaxy Note 10+
Oh I'd love that - but it's a system app and removing those without root is kind of... impossible? I can look into disabling it completely however - I never use it anyway. Since it's not a single app - any chance you got a link to the list of apps that need manual disabling?

Anyway, I'm still getting those damned warnings. :( The phone isn't constantly hot however, which is some improvement.
Package Disabler kills bixby proper.
You can also disable it with an adb edit. That's one of the first things I do.
Bixby is a hot mess best dump along the interstate... like Google Assistant it needs external servers for many of its functions. I may change my mind but it's eula is like eating dry hardtack for breakfast.
 

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    You need to find the root cause. It may be a 3rd party using one or more of the Samsung system apps running under Android services, lol Legend for there are many... all lumped together.
    A firewall with logging can help. Karma Firewall is what I use, uses almost no battery. Being rooted you have more options... use them.
    Malware is always a possibility.

    3rd party apps can cause hell. I don't allow any social media apps on the phone, ever.
    Try in safe mode... if things calm down it's likely a 3rd party app. If so start going through the installed apps.
    Clear system cache.
    1
    You need to find the root cause. It may be a 3rd party using one or more of the Samsung system apps running under Android services, lol Legend for there are many... all lumped together.
    A firewall with logging can help. Karma Firewall is what I use, uses almost no battery.
    Will try that, thanks!
    Being rooted you have more options... use them.
    The phone is NON-rooted. :(
    Malware is always a possibility.

    3rd party apps can cause hell. I don't allow any social media apps on the phone, ever.
    Try in safe mode... if things calm down it's likely a 3rd party app. If so start going through the installed apps.
    Clear system cache.
    Oh, safe mode! I'll try that too! Thanks!
    1
    OK, I'm baffled. I feel like I didn't really do anything but the phone is now running fine. Battery drain now might be better than ever! 😮

    Warms up on usage, obviously, but when idle it's nice and cool and battery drain seems minimal. I'll... leave it for a few days to see how this develops. It's very difficult to tell what the heck's the case here.
    1
    Kill wittle bixby... you read it EULA?☠
    Oh I'd love that - but it's a system app and removing those without root is kind of... impossible? I can look into disabling it completely however - I never use it anyway. Since it's not a single app - any chance you got a link to the list of apps that need manual disabling?

    Anyway, I'm still getting those damned warnings. :( The phone isn't constantly hot however, which is some improvement.