I found this:
"Samsung Galaxy S3 I9300 was released in May 2012 & I9305 was released in September 2013
Key differences between I9300 & I9305 are as follows:
1. 4G- LTE (Long Term Evolution):
For those wanting superfast downstream/upstream rates, I9305 offers support to 4G . Expect downstream rates as high as 95Mbps if in good coverage. Unfortunately, the best selling variant of Galaxy S3