These things only net you one or two orders of magnitude (and give you very little or even negative power efficiency gain), or maybe 3 for the gpu.
This pales in comparison to the 4-6 orders of magnitude induced by thoughtless patterns, excessive abstraction, bloat, and user-hostile network round trips (this one is more like 10 orders of magnitude).
Write good clean code in a way that your compiler can easily reason about to insert suitable vector operations (a little easier in c++, rust, zig etc. than c) and it's perfect performance in my book even if it isn't saturating all the cores
This pales in comparison to the 4-6 orders of magnitude induced by thoughtless patterns, excessive abstraction, bloat, and user-hostile network round trips (this one is more like 10 orders of magnitude).
Write good clean code in a way that your compiler can easily reason about to insert suitable vector operations (a little easier in c++, rust, zig etc. than c) and it's perfect performance in my book even if it isn't saturating all the cores