i had a PCIe 2 mobo paired with 1050ti
the performance jump was amazing (was using GT 630, so it's expected) even though my Pentium bottleneck it so hard (my GPU usage never reaches 60%)
i play GTA at 768p very high - normal settings and get 40-50 fps (bottlenecked, GPU usage was bout 20-40% went up and down depending on the area)
played skyrim with bout 100+ mod with all texture at highest (HD 2k, CBBE 4k, etc) and get like 30-60 fps (again, bottlenecked, GPU usage reach 47% at max if i recall correctly)
the GTX 1050ti is winning again 960 in some cases
and getting an older gen GPU is not worth i think (the driver supports, used stuff, warranty, etc)