The best replacement for physx is sli.

The best alternatives to physx are rated as following:
★★★★★  sli
★★★★★  havok
★★★★  bullet
★★★  no physx
★★  mantle
★★  eyefinity
★★  tressfx
★  directx 11
★  havoc
★  massfx
★  cuda
★  opencl
★  advanced physx
  dx11
  nvidia physx
  ageia physx

Your alternative for physx is not listed? Suggest!
Speaking about physx, one probably shouldn't forget about ati card.

Other search terms related to physx and their ratings are:
★★★★★ ati card
★★★★★ amd
★★★★ radeon
★★ amd gpu
★★ ati
★★ amd and nvidia card
★ 7970
★ amd card
★ amd and nvidia
★ sli
★ nvidia
★ nvidia card
★ amd cards
★ amd radeon
ati and nvidia
You have in mind a companion for physx and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of physx in all years. Click on graph for more.
physx
sli
havok