cpu usage and battery life

[conductor_bosh]

I've noticed recently that my nooks CPU usage is often maxed out at 800mhz even when just on the home screen with nothing running in the background. Also, juice defender claims to have improved my battery life by x1.04 in the last 24 hours, when just last week it said x2.67. Also, typing on this forum right now, my keyboard is being very laggy and unresponsive.

What's going on?

(Nook Color running CM7)