Hi Ankit,
My name is Mohammed Shuaib, an Independent Advisor and I'm here to assist you with the issue of Laptop lagging when plugged into power. Please follow the below to fix the issue.
Fix #1
Step 1:
Go to the search box next to the windows icon and type 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 Switchable Dynamic Graphics and then expand Global Settings
Step 6:
Click on drop under Plugged In and select Maximize Performance
Step 7:
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
Let me know the status after performing the above.
Regards
Shuaib
Independent Advisor