Size limit to Amazon S3?

[Proxurve Solutions]

Does anyone know if there is a size limit to transfer files to Amazon S3?  I am able to transfer small files (up to a couple Gigs) but when I attempt to transfer a couple files around 18 - 20Gig, the transfer appears to complete however the Transfers window and Cyberduck all together freezes.  I did allow plenty of time for the transfer to complete.  I have 500Mbps up/down so this should not take very long to complete and I allowed over 24 hours before I had to end the task via Task Manager.