For this I used a seperate program which runs very fast for a little number of planets.  
It's called the Picard intregrator and adapts the timestep in order to maintain its accurancy . For this configuration of planets the "timestep" was about 13000 hours .

Quote from ssc4k on 01/03/08 at 15:31:37:

We normally use the software provided in this Forum . That's Gravity Simulator . The modarator Tony also takes care for upgrades , which are announced in this forum and can be downloaded .  
Personally i also use a private integrator which has some advantages as accurancy but it is far off as userfriendly as the Gravity Simulator . It's rather complicated to use it as it needs much input . Maybe the integrator will one day be "integrated" in the software of Gravity Simulator .