I've noticed my Ubuntu Gnome 14.04 has been getting a bit sluggish lately - things like Gnome Shell overview animation are jerky where they were lightning fast, Elder Scrolls Online is stuttering and dropping to low FPS where I previously had a solid 50-60 fps. Out of interest I looked at the CPU History, and when running nothing but the system monitor, I was getting this:

That was 15 minutes ago. The 100% load seemed to be alternating between the cores.

PC specs:

• i3 2130 processor.
• 8gb DDR3 RAM.
• ASUS P8-Z77M motherboard.
• Samsung 128gb SSD

I've been trying to reproduce the problem, and while I'm not getting the 100% any more at idle, the system monitor is showing an average load of about 20-30%, that's with just Chrome and the System Monitor open. Oddly, if I touch nothing, it'll average out to about 20% - if I start moving the mouse around and do some typing, it's closer to 40%.

Is this normal? Any help appreciated, I wouldn't even know where to start here..