There's a data dependency between those 6 instructions so out-of-order execution unit won't be able to kick in as much but still ... each of those 6 instruction

There's a data dependency between those 6 instructions so out-of-order execution unit won't be able to kick in as much but still ... each of those 6 instructions takes only 1-2 cycles to execute. Perhaps a better question to ask then is: how many loops there need to be so that 6x {1, 2} cycles outweigh the SIMD version? (I wrote this initially as an EDIT in my response above but since you replied at about the same time, I am copying it here)