I mostly just want to know if an option is avaliable for the Nehalem processors. If it happens that the newest version of GCC has such an option, then I can always upgrade to that version. I believe that Barcelona is an AMD processor, so I'm confused as to how that would work for an Intel Nehalem processor. As for -mtune=nocona, I've tried and there was no performance gain. Thank you. Regards, Rayne > Do you mean you want to use an old version of gcc, issued prior to the > advent of -mtune=barcelona? That would reduce your performance potential > for vectorized code. It should be obvious, as Nehalem came later than > Barcelona, that there would be no optimization for Nehalem in older > versions. > You would have to experiment yourself to see whether -mtune=nocona helps > performance in your case. It's certainly not feasible to give you > recommendations covering all old gcc versions, even if we could guess the > other factors of your case. > > >-- >Tim Prince