# CPU throttling when plugged in



## dropout87 (Aug 4, 2022)

I have a Dell Inspiron 5558 with i5-4210u (up to 2.6 ghz) which throttles when plugged into charger. On battery, it reaches full turbo speed but when charging, it'll be max 1.8. I have tried disabling BD PROCHOT, switching charging cables with another Dell charger and changing windows power plans between balanced and high/ultimate performance but nothing helps. BIOS doesn't have any related options either. The only temporary solution I found is going to TPL --> locking MMIO --> unlocking it (which prompts the restart dialogue box) --> restart PC and this fixes the issue. The CPU will turbo fully even when charging, but its temporary. If I unplug and replug charger, put computer to sleep, shutdown or restart, it begins to throttle again. Any idea on why the MMIO lock/unlock temporarily fixes the issue and suggestions to fix this permanently? Thanks


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## Nikuuuuu (Aug 4, 2022)

Can you check your temperatures? It's probably thermal throttling and repasting your cpu is probably a good idea since it is an older laptop


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## dropout87 (Aug 4, 2022)

Normal use temps are around 50 C and when running prolonged benchmarks, it doesn't exceed 70 C.


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## beardrinksbeer (Aug 5, 2022)

dropout87 said:


> I have a Dell Inspiron 5558 with i5-4210u (up to 2.6 ghz) which throttles when plugged into charger. On battery, it reaches full turbo speed but when charging, it'll be max 1.8. I have tried disabling BD PROCHOT, switching charging cables with another Dell charger and changing windows power plans between balanced and high/ultimate performance but nothing helps. BIOS doesn't have any related options either. The only temporary solution I found is going to TPL --> locking MMIO --> unlocking it (which prompts the restart dialogue box) --> restart PC and this fixes the issue. The CPU will turbo fully even when charging, but its temporary. If I unplug and replug charger, put computer to sleep, shutdown or restart, it begins to throttle again. Any idea on why the MMIO lock/unlock temporarily fixes the issue and suggestions to fix this permanently? Thanks


Go to control panel > power options > change plan settings > chnage advanced power settings > go down to 'processor power management' & double click on it.
And change the minimum & maximum processor state like I have done to mine in the pretty picture  
I hope it helps


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## dropout87 (Aug 5, 2022)

beardrinksbeer said:


> Go to control panel > power options > change plan settings > chnage advanced power settings > go down to 'processor power management' & double click on it.
> And change the minimum & maximum processor state like I have done to mine in the pretty picture
> I hope it helps


I have tried your suggestion but it didn't help. Actually, I found out that just restarting my computer (even without Throttlestop) fixes the issue temporarily. Shutting down, unplug/replugging the charger, sleep mode etc will cause the CPU to begin throttling but if I restart the device with charger plugged in, it'll temporarily fix the issue. What an odd issue! I have tried searching different forums/sites for a solution but no fix yet.


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