Hi Thomas, Is this a factor...? """ Note that the effectiveness of aligned attributes may be limited by inherent limitations in your linker. On many systems, the linker is only able to arrange for variables to be aligned up to a certain maximum alignment. (For some linkers, the maximum supported alignment may be very very small.) If your linker is only able to align variables up to a maximum of 8 byte alignment, then specifying aligned(16) in an __attribute__ will still only provide you with 8 byte alignment. See your linker documentation for further information. """ http://gcc.gnu.org/onlinedocs/gcc/Variable-Attributes.html http://gcc.gnu.org/onlinedocs/gcc/Type-Attributes.html Do you know if the linker being used supports the alignment your code is requesting on your platform? Sincerely, --Eljay