Hello everyone, I'm not sure I should be asking for this here or in apple or intel forums, but anyway, I have a mac book intel core duo and I'm running mac os 10.6.7. I have xcode 3.2.6 and the default compiler is gcc 4.2, and it's the last version of gcc supported in xcode yet. I lately started to use intel SSE for some linear algebra routines and I would like to use _m256 type but I couldn't find it in the xmmintrin.h header, is this because It's not supported by the hardware , I bought my mac on 2007, or I just have to update the intel SSE headers. thanks for all -- View this message in context: http://old.nabble.com/m256-missing-from-%3Cxmmintrin.h%3E-tp31388723p31388723.html Sent from the gcc - Help mailing list archive at Nabble.com.