Which version of LR did you upgrade from? As earlier versions had a different process version. PV 2012 [LR5] was quite different in many ways from PV2010 [LR4].
Slider positions can be quite different for what may seem similar effects in different PVs.
However, +100 Clarity in PV 2012 with nothing else done seems identical to +100 Clarity in PV2010. But with other parameters altered, clarity in each PV can then seem very different.
Interestingly if looking at two variations of an image with PVs 2012 + 2010, they look a tad different from each other on second monitor in survey mode, but identical on main monitor when you flip between them.