does where its manufactured make a differnce in dual core overclock?

just wondering like previous intel chips i think the ones from costa rica overclock the best is this still true with the dual core intels? anyone notice a pattern in this..just wondiner if i decide to go that route to find one in costa rica .. thanks!

with the 6x0 and the 5x0 and the 8x0 from what I have gathered, it doesn't matter.