The best replacement for quad sli is tri sli.

The best alternatives to quad sli are rated as following:
★★★★★  tri sli
★★★★  quad crossfire
★★★  dual sli
★★★  4 way sli
★★  3 way sli
★  3-way sli
  gtx 285 tri sli

Your alternative for quad sli is not listed? Suggest!
Speaking about quad sli, one probably shouldn't forget about gtx 295.

Other search terms related to quad sli and their ratings are:
★★★★★ gtx 295
You have in mind a companion for quad sli and it is not yet here? Propose!



Google Trends

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quad sli
tri sli
quad crossfire