The best replacement for i7 is i5.

The best alternatives to i7 are rated as following:
★★★★★  i5
★★★★  xeon
★★★★  amd
★★  quad core
★★  core 2 duo
★  i5 for gaming
★  phenom
★  i3
★  i5 haswell
★  core 2 quad
★  a10
★  phenom ii
★  amd a10
★  amd fx
★  sandy bridge
★  i5 gaming
★  a8
  8gb ram
  i5 laptop
  quad
  xeon e5
  fx
  i5 processor
  core i5
  i5 macbook pro
  core duo
  q9650
  x6
  i5 benchmarks
  amd phenom
  intel core 2 quad
  i5 processors
  fx 8350
  xeon processor
  phenom x4
  6 core
  amd quad core
  dual core
  intel core i5
  i7 extreme
  phenom ii x6
  q6600
  am3
  xeon quad core
  e5
  duo core
  intel i5

Your alternative for i7 is not listed? Suggest!
Speaking about i7, one probably shouldn't forget about ecc memory.

Other search terms related to i7 and their ratings are:
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i5
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Google Trends

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i7
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