Here's one for you. My laptop at work does something weird. If I've
had it unplugged from power for a while, it runs quite slow when I put
it back in the dock while on line power.

It's running windows 8.1 (I know, that's probably half the problem),
has 8GB of RAM and an ssd in it.

If it's fully charged and on ac power, it runs fine, or when it's
running on battery it's fine, just gets sluggish when it's charging the
battery up from a charge lower than 100%.

Any ideas?