i have one little strange problem with upd3. it took some time to investigate, though...
i found that i have two programs which took much more time loading than with upd2. one is "everyday organizer", or better the "alarmist" part of it and the other one is yam.
the tests i did for alarmist have been performed on a *clean* os4.1 installation. means, just the naked os was installed. just 2 needed assigned and the prefs added.
alarmist:
i usually start it in wbstartup. for the test i started it manually. it should open a window showing me upcoming events.
with upd2 it takes from double click to the window showing about 1-2 seconds.
with upd3 it takes (much) more than 5 seconds.
for yam it looks like this.
when starting yam the info window is shown telling me what yam is doing... the step "lade postfächer" (loading mailboxes?) takes about 2-3 seconds longer than using upd2. this is very noticable

after trying and trying i found the culprit on my system. it is dos.library.kmod in the kickstart folder:
upd3: dos 53.76 (04.08.2011)
upd2: dos 53.58 (21.04.2010)
if i use the dos.lib from upd2 everything is fine. using the one from upd3 the slower loading speeds are visible...
anyone else noticing that?
thanks and regards
michael