It's possible but still seems high.
For me to run 500X9 on my EP45 I need.
1.38 vcore in BIOS
1.34 VTT, or Term
1.30 on the NB or MCH
All boards and chips may vary, but you should be in this range by .05
I could do wonders with it as P45 clocks AGES better than X48 that i now have...
I think i used to have 1,38ish on P45 but i am not sure...
What i am sure about is that P45 needs much less voltage than X48 does for the same or even more FSB!