Practically in 99.9% of cases: no.
Theoretically: maybe. You won't be passing the implicit this
parameter to every function, and not passing that could save you bytes and the time passing those bytes. The compiler may well optimise it away though in any case. If profiling has shown one of these functions is on your hot path, it might be worth considering.
However, I'd argue you should still do this anyway, because it makes it clear to anybody looking at the code that your static function doesn't act on any object state. That's far more important than any discussion about memory or performance.