The best replacement for i3 is i5.

The best alternatives to i3 are rated as following:
★★★★★  i5
★★★  core 2 duo
★★★  i7
★★  amd
★★  pentium
★★  dual core
★  quad core
★  i5 processor
★  a6
★  amd a6
★  i5 imac
★  core i5
★  amd a8
★  i5 gaming
★  awesome
★  a8
★  i5 laptop
★  celeron
  a10
  core 2
  fx 6300
  g2
  core 2 duo imac
  i5 benchmark
  core duo
  p6100
  phenom
  turion
  streetpilot i5
  core 2 quad
  intel pentium
  xeon
  i3
  i5 performance
  i5 comparison
  i5 processors
  pentium 4
  pentium dual core
  i5 better
  ping i3
  duo core

Your alternative for i3 is not listed? Suggest!
Speaking about i3, one probably shouldn't forget about gnome.

Other search terms related to i3 and their ratings are:
★★★★★ gnome
★★★★★ gtx 660
★★★★ xfce
★★★★ 8gb ram
★★★★ gtx 770
★★★ gtx 780
★★ core 2 duo
★ kde
★ hd graphics
★ gtx 760
★ ecc
r9 270x
You have in mind a companion for i3 and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of i3 in all years. Click on graph for more.
i3
i5
core 2 duo