It's not usually a big difference, but on modern Intel there is a some difference in performance between the different CMP/JCC options. The more common ones wi

It's not usually a big difference, but on modern Intel there is a some difference in performance between the different CMP/JCC options. The more common ones will "fuse" with the CMP and be executed as a single µop, but the rarer ones (like JO and JS) do not fuse with CMP, and thus can add a cycle of delay (and have the overhead associated with executing another µop). The optimization is called "macro op fusion". Details here https://en.wikichip.org/wiki/macro-operation_fusion https://en.wikichip.org/wiki/macro-operation_fusion and here https://www.agner.org/optimize/microarchitecture.pdf https://www.agner.org/optimize/microarchitecture.pdf (pages 108 and 125).