Leaderboard

Yup, it is interesting to have a cousin with the same laptop :D. But I've seen people couldn't get the 3dmark to run on i7 quad with 65w adapter, simply crashing, so I don't really know if it is something from the motherboard. I don't think it is from the motherboard because I changed the motherboard from 2560p to 2570p on my laptop like a month ago, I will try the battery and the 90w adapter and I will tell you then.

Try inspecting the board (traces, pins, connector etc.). There must be some kind of damage to the board.

I think you maybe read an obsolete post? My exam has been completed since June. I'm now as free as a bird!

Yes it is either your laptops specific battery because I have a 45w CPU running fine on battery, but with degraded performance, this leads me to my second point : Or either, it is because you try to run the CPU at full speed when on battery, because not any laptop of this grade of CPU even in 2019 will run at full speed (as if it is plugged in) without having sudden shutdown issues.