My EliteBook 8440p laptop slows down after plugging in.

[JackCaine_217]

Whenever my laptop is low on battery and i plug the charger in it slows down so much and starts lagging after a few minutes, and i have to wait until the battery goes upto 60 or 70%. After that, it goes back to normal.
I have tried so many ways to solve this problem but so far i have had no luck. I've tried reinstalling the windows 3 times. I went from windows 7 to windows 10 then back to 7 and now i'm using windows 8.1. I tried formatting all the files from C and installing a new windows but that didn't work either. I've tried replacing my battery, but that didn't work either. I've searched on many forums but so far, i've found nothing useful. And before you ask, no its not am overheat issue. My laptop stays at 50 to 60 degrees centigrade. And i've also tried cleaning all the dust out but nothing seems to be working for me.
When i installed windows 10, it did go back to normal for a few days but the problem came back again. On battery the CPU usage is normally 4 to 6% but when it starts lagging it skyrockets to 50 to 60%. I've also tried changing the power settings to high performance but that didn't work either.
My specs are:

Windows 8.1 Pro x64bit
Inter Core i5 M520 2.4GHz
4 GB RAM
HDD 250 GB
Nvidia NVS 3100M GPU.

Can someone please tell me whats wrong with my laptop.?

 

[webworkings]

It sounds like it actually may be your charger cord, the battery, or a combo of the two.

I would start with the cord though. If a cord isn't putting out the correct amount of power, it will start to charge the battery less and finally not at all, when plugged in. It may well even turn off the laptop due to the power issue. Making it only usable with the battery removed, or chargeable when the laptop is off. I would try a different charger cord and see if that resolves it.

 

[JackCaine_217]

Thanks for replying. I'll check that out.