No problem for the help...I try my best...
As to voltages, I am unsure, as each board/cpu/memory combo, even of the same parts, will have different requirements. The board should be able to go 400 without any adjustment, but maybe not...
you can use many programs, OCCT, Prime95, IntelBurnTest, Cinebench...personally, I run them all...If i cannot run 48-hour tests of each app without errors, it's not stable enough for me.
That said, I run 533x7.5 for 4ghz on X48...you should be able to get the same, if not better...maybe a little less....
P45 is very varied in it's clocking...some boards do 600FSB, some barely top 510...you just gotta try, test, try, test, try, test, until you feel comfortable.
Just be aware that you can corrupt your OS, so please back up any important data before attempting anything.