Not necessarily. Even though PS/2 operates with a superior protocol, latency-wise, the clock speed is atrocious, resulting in an effective polling rate of about 1500hz, give or take. We could account that it doesn’t need to wait for request to send keystrokes like USB keyboard do, effectively doubling it even more, but then we’d have to account for whatever delay Super I/O chips introduce and I’m not qualified to talk about that. But, if your keyboard is not from a dollar store shelf then it probably runs on at least 1000hz, at which point we are talking about sub-millisecond difference which would be quite hard to notice. 4000hz keyboard definitely beats PS/2 though.