With PeopleTools 8.51 a feature was introduced which detects the fields changed by the user and ONLY sends these. The upload savings in payload size of this are very significant. I found this didn't work all the time in 8.51 and sometimes, for no apparent reason, would revert back to old behaviour. Of course on a high speed office network users wouldn't notice but on slow networks this new form post feature was massively beneficial.
This feature looks like it's had some improvements in 8.52 and seems to more consistently do the smart post back of only changed fields.
If you haven't got a clue what I'm talking about then watch this video.... it may help understand this simple but effective new 8.52 feature.
Nice one PeopleSoft developers!