Does encrypting the Xoom tablet use battery faster? I recently decided to encrypt my Xoom tablet.  The process went smoothly (full power, plugged in the whole time, took about an hour) but since the encryption, it seems like my battery life has decreased.  With moderate usage, I used to get close to two days worth of usage before the encryption, but now my battery usage meter has me at 15% after 23 hours.

I found this thread on the Motorola Owners' Forums but that is about it.
Encryption is a fairly CPU intensive process, so using more battery is not unexpected.  Though it depends a lot upon the apps you use and how much they read/write to the storage.  I would expect that an 'idle' Xoom with encryption would last just as long as one without, but if you use an app that does lots of little writes to disk, it will end up using more CPU.

The encryption happens at the block layer.  This means that small writes to the disk require a read, a decrypt, an update, and then writing the block back.

I don't see any useful stats about the actual CPU overhead.  (Android is using the 'dm-crypt' module of the Linux kernel to do the disk encryption.)