The last time I reported about this topic was 03/20/2012, http://community.norton.com/t5/Norton-Internet-Security-Norton/141-MB-LiveUpdate-only-22-hours-after-previous-LiveUpdate/m-p/682983#M198708
...but I'm starting a new topic of the same thing here.
I just spent a 45-minute very smooth LiveUpdate session to accept download and install of 9 update items. The actual install time was maybe 11 minutes. The LiveUpdate was 140.72 MB and only took maybe 30 minutes to download. I have been taking LiveUpdates nearly every day for over a month and those ones were much smaller, like about 2 to 4 MB at each daily session, or less if more than one were done during the day.
Today's LiveUpdate of 140.72 MB of 9 itmes were these, all successful:
2011 Iron Revocation List
2011 IPS Definitions (instrusion detection engine)
2011 Iron Whitelist
2011 Virus Definitions
Activity Map Data
2011 Behavior and Security Heuristics
2011 AntiSpam Definitions
2011 Web Protection Definitions (Antiphishing to verify authentic Web sites
Pulse Update (latest pulse update from Symantec Security)
System: Windows XP, service pack 3; laptop, 2.0GHz processor, 30 GB harddrive, 512 MB RAM; NIS version 18.7.1.3