After switching my hard disk to a solid state disk (Intel X-25M G2) this bug disappeared. This supports the assumption that the delay is caused by accessing lots of files on the hard disk as a task like this benefits considerably from the low access times of a solid state disk.
After switching my hard disk to a solid state disk (Intel X-25M G2) this bug disappeared. This supports the assumption that the delay is caused by accessing lots of files on the hard disk as a task like this benefits considerably from the low access times of a solid state disk.