Difference between Equanimity which is diversified and Equanimity which is unified In the Potaliya Sutta, Buddha says,


  So too, householder, a noble disciple considers thus: ‘Sensual pleasures have been compared to fruits on a tree by the Blessed One; they provide much suffering and much despair, while the danger in them is great.’ Having seen this thus as it actually is with proper wisdom, he avoids the equanimity that is diversified, based on diversity, and develops the equanimity that is unified, based on unity, where clinging to the material things of the world utterly ceases without remainder.


What is the difference in Equanimity that is diversified and Equanimity which is unified?

The complete sutta can be found here...http://suttacentral.net/en/mn54
The Pali version of this expression identifies equanimity that is diversified as upekkhā nānattā nānattasitā and equanimity which is unified as upekkhā ekattā
ekattasitā.


  Evameva kho, gahapati, ariyasāvako iti paṭi­sañcik­khati:
  ‘rukkha­phalū­pamā kāmā vuttā bhagavatā bahudukkhā bahupāyāsā, ādīnavo
  ettha bhiyyo’ti. Evametaṃ yathābhūtaṃ sammappaññāya disvā yāyaṃ
  upekkhā nānattā nānattasitā taṃ abhinivajjetvā yāyaṃ upekkhā ekattā
  ekattasitā yattha sabbaso lokāmisūpādānā aparisesā nirujjhanti
  tamevūpekkhaṃ bhāveti
  Potaliyasutta [Pali]


Following excerpt from Excursions Into the Thought-World of the Pali Discourses by Bhikkhu Analayo explains them in detail.


  The unified equanimity of deeper Jhāna experience is considerably more
  refined than worldly types of equanimity that are based on diversity,
  upekkhā nānattā nānattasitā
  
  Excursions Into the Thought-World of the Pali Discourses
   By Bhikkhu Analayo


So in summary,
equanimity that is diversified = undeveloped mind
equanimity which is unified = a mind at Jhāna level