Inspiron 3558, lags while charging

Robert there's no solution until you give me a modified bios. it's a throttling issue, the laptop runs fine on battery so just tell me where can I get good bios that won't throttle my cpu or gpu.

ahhh, found what you are talking about with Bios.

You cant disable Intel Speedstep.

Try another charger and I bet it works.

Download Core Temp and report what CPU temp is while plugged in and throttling. 

Go into Windows Power Management and verify it is set for maximum cpu performance when plugged in.

Same with the graphics card setting you find there.

Get back to us. 

Googling it I am finding many found it was a bad Dell charger ...

http://www.tomshardware.com/answers/id-3215066/slow-cpu-speed-plugged.html

I have disabled speedstep, turbo boost and c states too from the bios but problem still persist

I have set power options to maximum and same with the graphics card, it's not windows problem coz I have reinstalled windows , it's probably that a sensor has gone bad and sending false bdprochot signals and cpu is underclocking while charging

If you need additional assistance, please contact me privately. Be sure to include your personal information and your computer's service tag number. Thanks.

Look at the plug from the charger that goes to laptop. That tiny center pin if bent or broken, the PC will think its an unknown charger and lower cpu. Something with the charger is out of Spec.

The internet is flooded with stories about this very same issue. All were the charger.

no i have changed the adapter still the problem persist

on battery pic1

on charging pic2 (stuck at 500mhz)

on battery pic1

on charging pic2 (stuck at 500mhz)

core parking 

on charging

1 cores parked

2 unparked

Hi, my name is Vishnu Gopan G M, these settings can help you with this problem. you can use these settings at your own risks

Step 1:
Go to the Power option, Edit Power plan then click to open it.

Step 2:
Click on Change Advanced Power Settings

Step 3:
Expand Processor Power Management and then expand Maximum processor state

Step 4:
Change the Plugged In to 100%

Step 5:
Expand Multimedia Settings and then expand When playing Video

Step 8:
Then under Plugged In select Balanced

Step 9:
Click Apply and then click OK

Step 10:
Restart PC and verify

Here I provide a registry key link for these settings, you can enable or disable these settings by downloading the file (Use this when not on your PC or laptop)

https://www.mediafire.com/folder/jl6jh3dtvgfw8/Vishnu_Gopan_G_M 

Your post doesn't indicate if you've been able to perform a systems diagnostics yet. Please run Dell SupportAssist or press F12 at startup, make a note of any error messages found and post back.