I did not perform an applied experiment, more a literature and benchmarks review; but Mayhem and Nubok[0] say this: > Near branches with the 0×66 (operand size

I did not perform an applied experiment, more a literature and benchmarks review; but Mayhem and Nubok[0] say this: > Near branches with the 0×66 (operand size) prefix behave differently. One type of CPU clears only the top 32 bits, while the other type clears the top 48 bits. This is more than enough to send your code into wrong address and possibly cause a crash. [0]: https://superuser.com/posts/383943/ https://superuser.com/posts/383943/