S3 freezing issues

Ok so, i own an international galaxy s3, i didn't have any problems with it, until the 4.1.2 update came along, it started getting laggy and most important of all, it started freezing, it usually happened once every two days or so, but it still was nerve racking, cause it would do that while doing something important, so i decided to do a factory reset, everything went fine, but it started freezing again, this time it freezes a lot when the phone is connected to the internet, especially with WiFi on,and when i enable sync, it freezes and it gives me a com.google thing error, it's starting to get really annoying, any suggestions?

EDIT: opening heavy duty apps like games, make the phone freeze instantly, i'm wondering if it has something to do with the RAM...