Replying to an old post but I hope you will see this!
I recently swapped the 64GB card in my S3 (9305 running RevolutionRemix ROM) for a Sandisk 128GB card. It appears to work OK, the phone sees 119GB of space on the card and I have already filled more than 64GB so the extra capacity is there, but lately I have noticed the phone lags a lot and has also been crashing quite frequently which it didn't before. I am not sure of the exact timing because you never notice the pattern until it has been happening for a while, but I suspect the problems started around the time I put the 128GB card in. I don't remember formatting the card, it probably came already formatted so I just used it as it was. I guess I could backup all the contents and try formatting it in the phone to see if that makes any difference.
Have you noticed any issues since using the 128GB card? Does a bigger SD card require more internal memory or processing power to use it?