I have the same lip synch problem with freeview on a Samsung UE40H6400 that I bought in June. The problem is so severe on certain channels it is definetely unacceptable.
I have several emails from Samsung admitting there is a known problem. They have stated that their technicians are working on "a software update which will cure this issue" but cannot comment on when this will be, but suggest I check regularly for updates! There have been two updates since, but neither have fixed the problem. Fortunately Richer Sounds have agreed to replace the TV if Samsung don't fix it, and now my patience is running out, so I may have to take the replacement option.
If any of the What Hi-Fi guys are interested, I can forward copies of my email exchange with Samsung.
Have you downloaded the latest firmware released on the 18th august, AFAIK it is supposed to cure lip-sync problems.
Click on support underneath the tv or scroll to the bottom of the page.
Thanks Simon. However, Samsung had already directed me to that page, and like I said, the two updates issued since did not fix the problem.
I have just bought this TV and I also found the lip sync issue disapointing. I have found that if you go to menu - sound - additional settings and change the audio delay it seems to have fixed it. Not had this problem with other TVs so it's a bit worrying...