I have a new laptop Lenovo ThinkPad L520 (7859-5BG) Core i5-2520M(2.5GHz) with 4GB RAM.

Having installed Ubuntu 11.10 32-bit, while browsing with Chrome on GNOME classic (no effects), I noticed 173% CPU usage by chrome browser process, and the system slowly got very very slow,

Now, at this stage as I removed the power adapter, the system suddenly got faster (and stopped the lagging behavior) and CPU usage drops down to 48% !!

Observation 1:

I was browsing through chrome when my system seemed to be seriously lagging, so I killed chrome to see if it gets any faster. But there remained no difference. Notice that CPU usage was a bit strange here. It showed no high activity, but as soon as I would click on applications in gnome panel, it would shoot CPU usage to 70, or 80 or 90 or 143% etc. depending on how quickly i clicked back and forth. At this instance I removed by AC adapter of my laptop, and suddenly system got fine. So i again clicked on gnome panel, and noticed that it now took only 7% or 12% or 13% at max, with same kind of clicks in application menu.

Observation 2: At the other times, with AC adapter plugged in, top indicates four instances of chromium taking 90%, 60%, 47% and 2% (for example), and then once I take out the AC adapter same processes take lesser CPU all of a sudden

Intermediate conclusions: What does this indicate ? I cannot figure out any "other" process in "top" that is suddenly being triggered, its the same process that hogs up my CPU once AC power is plugged in !

NOTE: the problem is now CONFIRMED, as i can repeat that when I have power adapter plugged in !

Can anyone tell me what exactly does this indicate ? What is wrong, is it some bug with power management or what ?