The best replacement for sp4 is zv4.

The best alternatives to sp4 are rated as following:
★★★★★  zv4
★★★★  zcon
★★★★  btl
★★★★  btl n2
★★★  dc lvl 5
★★★  orion hcca
★★  fi bl
★★  ssa evil
★  aq hdc4
  sp3
  xp sp2
  bl

Your alternative for sp4 is not listed? Suggest!
Speaking about sp4, one probably shouldn't forget about windows 2000.

Other search terms related to sp4 and their ratings are:
★★★★★ windows 2000
You have in mind a companion for sp4 and it is not yet here? Propose!



Google Trends

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sp4
zv4
zcon