My partner's S3 has got seriously slow. I've tried the usual tricks, deleting cache, disabling 's voice and pretty effects. I have an S4 and used another S3 beforehand (not her one) and didn't really notice a difference in performance. Her one is painfully slow. She won't let me reset it, which I've done earlier this year.
How can I actually test it? I've run Antutu on it and it scores fine, though if any S3 owners want to chip in south their scores that would help.
Does the size of the SD card have any effect?

The ultimate solution maybe for me to get a new phone and hand her my old one...