Here is the C minor arpeggio played in 8th position.  It is made up of the notes:

C  Eb  G

If we made the Cm arpeggio a Cm7 arpeggio we would add a Bb.   A Cm7 minor arpeggio is made up of the notes:

C  Eb  G  Bb

Even though not an arpeggio, it is a good idea to see how both the Cm arpeggio and the Cm7 arpeggio relate to the Eb/Cm Pentatonic scale.

The notes of a C minor pentatonic scale are:

C  Eb  F  G  Bb

The notes of a Eb major pentatonic scale are:

Eb  F  G  Bb  C