High CPU after BVH import and click on armature


I need some help with a motion capture issue.

When I import a BVH file and click on the armature blender is using one of my two kernels completely for some time.

I am using Blender 2.69+svn61239+git201401010427.d8f4cb9 on an AMD Athlon 64 X2 5600+/ Zorin 7 (Ubuntu). Installation was via PPA.

However the problem was also apparent on the pre-installed version 2.6.

I tried different motion capture files and I am not having the problem on a windows XP machine/Intel Centrino.

I would be very grateful for any help.