In bug 601186, Sebastian found out that a reason for the high cpu usage is the flag "write meta data into file".
Deactivating solved my problem (but it ain't a solution!)

This is likely seen by many people but more than one problem so in an attempt narrow the list down a bit it would be helpful if people experiencing something like this could perform some tests:

Always ensure that you are using the latest maintained Banshee version, testing against a Daily snapshot such as provided in the Banshee Daily PPA for Ubuntu would be extremely useful as well. As changes occur after the release of an version (except daily snapshots by definition) it might also be a good idea to look at the stable branch on our code repository:  http://git.gnome.org/browse/banshee/ (the stable-x.y with the highest number)

While this is happening try putting the cursor over the little throbber in the lower left corner to see if Banshee is doing anything else, such as analyzing songs using Mirage or applying organizational changes requested (Writing metadata to files and reflecting it).

Alternatively you can try running banshee-1 --debug and looking at the terminal output to see if anything is going on.

Also if you are on the SQLite 3.7 branch ensure that you are using a version without currently know performance regressions, as of this writing this means 3.7.3.

finally exit Banshee and run:

sqlite3 ~/.config/banshee-1/banshee.db "vacuum; analyze;"
(may require you to install additional software)

This will optimize your database and should rule out the database as being a
problem.

It would also be helpful for sufferers to provide a list of the extensions in use and as well as which versions of the Banshee and Banshee Community Extensions packages are installed. Further testing disabling and enabling features one by one, restarting Banshee in between changes and recording any changes to the problem as changes are made.

Thank you.

Please feel free to reopen this bug if you can provide the information asked for with newer banshee version.

Just realized that I can reproduce this on my Ubuntu 10.10 machine running Banshee 1.9.3.  During playback, `top` and Gnome System Monitor both report that Banshee uses around 23-25% CPU.  For comparison, Totem settles in to 6-8%, playing the same 160kbps mp3.

Some vitals:

$ sqlite3 --version
3.7.3

$ mono --version
Mono JIT compiler version 2.6.7 (Debian 2.6.7-3ubuntu1)

$ banshee-1 --version
Banshee 1.9.3 (1.9.3)

$ uname -a
Linux michael-desktop 2.6.35-26-generic #46-Ubuntu SMP Sun Jan 30 06:59:07 UTC 2011 x86_64 GNU/Linux

Plugins:
Wikipedia
YouTube
Audio CD
File System Queue
Play Queue
Apple Device Support
Mass Storage Media Player Support
MTP Support
Amazon MP3 Import
Amazon MP3 Store
eMusic Import
Last.fm Scrobbling
Miro Guide
Ubuntu One Music Store
BPM Detection
Cover Art Fetching
Importers for Amarok, etc etc
Metadata Fixup
MPRIS
Multimedia Keys

The throbber isn't spinning, and when playback is stopped, Banshee's CPU usage drops to ~0%.  I have gapless disabled, but all of the other general preferences are enabled.  I haven't had a chance to test my git build of Banshee yet, but I'll report back when I do.

I think that Bug 647144 was the cause of this.  After that bug was fixed, Banshee's CPU usage for me dropped to between 8-10% during playback, which is much more reasonable, and pretty similar to other gstreamer based media players that I tested.

I'm closing this as a duplicate of Bug 647144, even though this one was reported first.  The version of Banshee in an up-to-date Ubuntu 11.04 includes this fix, as does Banshee 2.0.1 and Banshee 2.1.  If you still see this problem in any of those versions of Banshee feel free to reopen this report.

*** This bug has been marked as a duplicate of bug 647144 ***