a 9600 pro outperforms a Ti4600, and a 9600 se does not cut memory in half, it is the same but with slower clock speeds as a 9600 pro. I know of people who have overclocked their se cards to pro specifications
I have nothing against the Ti4600, it is a great card, I'm just saying most people would prefer the ATI 9600's because they do run faster
what it would come down to in this case is their price; if a Ti4600 is half the price of a 9600 then by all means buy it as it does perform well for quite a lot of games