Why is my Acer Aspire E15 running slower when plugged in than on battery?

Question

I am working on an Acer Aspire E15 (ES1-511-C590) running Windows 8.1 X64 with all the latest patches. It is running significantly slower while plugged in than when running off battery.

Yes, this is counter-intuitive, and yes, I have checked the power settings.

No, this is not a subjective analysis. I ran PerformanceTest 8 on the system both plugged in and while running off battery. Here are the figures from each test - those on the left are while it was running off battery, those on the right while plugged in:

Overall: 600 / 186
CPU:     1024 / 275
2D:      193 / 48
3D:      152 / 41
Memory:  757 / 772
Disk:    681 / 759

Answer 1

1. Have you adjusted the settings in Control Panel\All Control Panel Items\Power Options\Edit Plan Settings, Advance options, which have separate options for On battery and Plugged in? That is the most likely cause of the issue, particularly active vs. passive cooling in Processor power management. See 13 Ways to Save Power for more information, and Power Options if the cooling policy is not shown.

2. Some Windows maintenance tasks, e.g. disk optimization, can be deferred while on battery, but resume with vengeance when plugged in. Check Task Manager (or Sysinternals Process Explorer) to see if there are running Scheduled Tasks using up CPU time. If that is the issue, let the tasks finish to keep the laptop healthy, and then it should speed up.

Answer 2

Some win8.1 versions are configured to safe power while not plugged in so it will enabled some tasks to keep your computer "healthy". If you want to disable the you can refer to this tutorial.

Answer 3

This is really weird...

I found some references to event logs sometimes causing these issues, so I cleared out some of the event logs on the system and now the performance test when plugged in is similar to that when running on battery (I have both set to utilize the most system resources).

I have no clue why this would be so...but it seems to be.

Answer 4

I had the exact same problem!! I solved it by:

Control Panel - Power Options - Change plan settings (on the right of the your power plan) - Change advanced power settings - scroll down and click on 'processor power management' - Maximum processor state - the 'plugged in' option was 0% while the 'on battery' was 100%, I simply put 100% in 'plugged in' (and kept 'on battery' 100% as well) and it worked instantly...I was using the internet with no hassle whatsoever and the laptop itself wasn't slow anymore :)

Hope this helps.