Thanks Carlo, I agreed with your reasoning, I just need some time to make up mind..CMU does not require a GRE Subject test, as you probably know. If you have exceptional math grades already, they speak enough for themselves already, so further proof that you are good in math would not really strengthen your application that much. First round is probably your best bet (the program does fill up as time goes by) - if I were you, I'd apply ASAP.