Jens M Andreasen wrote: > Comparison to the other two versions with gcc -O3 -msse > -ftree-vectorize, suggests a slight advantage over the original I would propose something like "-march=prescott -O3 -ftree-vectorize" or "-O3 -sse3 -ftree-vectorize". > With icc -O3 -msse the difference is even more pronounced: And something like "-O3 -xT" here. - Jussi