Need Help with 4G4A+ , P4 1.6A , DDR333 or DDR266

Hi, i`m new here.
I got some question for you;

1) I`d like to know if i can use 1 pcs of DDR333 512 Mb or 2 pcs of 256MB and the CPU 1.6A without overcloking, or i definitively must use DDR 266 without OC CPU ?

2) The only way to use DDR333, is it overcloking the CPU ?

Please need help, any question say it.....

See ya....