500 mg test vs 750 mg test

What to expect? I know that results obviously vary from person to person, but so far, I have ran two cycles. Both cycles were 500 mg test. Threw in a bit of Anadrol with the first blast, but second blast was purely 500 test only. I noticed a big decrease in rate of gains going from my first cycle to my second cycle, which I know is to be expected no matter what. But I have decided my third blast will be 750 test, so I'm curious on roughly what I can expect going from 500 to 750. Any insight is greatly appreciated.