In cases where there is no PCB with PS/2, do you know if the adapter when connected to PS/2 has the exact same behavior or are is it a lesser/compatibility mode

In cases where there is no PCB with PS/2, do you know if the adapter when connected to PS/2 has the exact same behavior or are is it a lesser/compatibility mode without the full benefits? Anytime I sit at a machine where the USB chip happens to reset, I wish it would use PS/2. It's just not the same, and I'm not even using n-key-rollover.