Late 2012 27 in. iMac 2K (A1419)

• Late 2012 2.9 GHz i5
• Late 2012 3.2 GHz i5
• Late 2012 3.4 GHz i7

Late 2013 27 in. iMac 2K (A1419)

• Late 2013 3.2 GHz i5
• Late 2013 3.4 GHz i5
• Late 2013 3.5 GHz i7

Late 2014 / Mid 2015 27" iMac (5K)

• Late 2014 3.5 GHz i5
• Late 2014 4.0 GHz i7
• Mid 2015 3.3 GHz i5

iMac (Retina 5K, 27-inch, Late 2015)

• 3.2 GHz Core i5 (I5-6500)
• 3.3 GHz Core i5 (I5-6600)
• 4.0 GHz Core i7 (I7-6700K)
  
  

Mid 2017 A1419

• Mid 2017 3.4 GHz i5
• Mid 2017 3.5 GHz i5
• Mid 2017 3.8 GHz i5
• Mid 2017 4.2 GHz i7

Mid 2015 27" iMac (5K)