Acer Aspire slows down

[GTP]

I have a client with an ACER Aspire S5-371 laptop that has an issue while charging.
Whenever its plugged into mains the laptop slows to a crawl.
Gaming frame rates drop to about 8 fps, youtube video's stutter and everything seems to generally slow down.
Running on battery is fine.

It has recently had a new battery fitted but it was doing the same thing before the battery was replaced.

Any suggestions/help appreciated
TIA

 

[Mick]

Is the CPU being thrashed when this happens?

 

[Diggs]

Have you checked the charger? Is it OEM?

I had an HP Split X2 recently that was stuck at .8 Ghz even with an OEM charger. I flashed new firmware and it took off again to normal speeds.

 

[GTP]

Is the CPU being thrashed when this happens?

No really being thrashed. It's an i7. Opening/saving a word doc, opening a browser, opening user folders are all noticeably slower when it's on the charger.

 

[GTP]

Have you checked the charger? Is it OEM?

I had an HP Split X2 recently that was stuck at .8 Ghz even with an OEM charger. I flashed new firmware and it took off again to normal speeds.

Charger is OEM original. I tried a Huntkey Universal but got the same result.

The BIOS flash might help and I'll do it ASAP