What resource do I need to upgrade for Windows to reject my password faster? [duplicate]

Why does it take so long (relatively) to say "incorrect password" ?

It doesn't. Or rather, it doesn't take the computer any longer to determine that your password is incorrect compared to it being correct. The work involved for the computer is, ideally, exactly the same. (Any password verification scheme that takes a different amount of time based on whether the password is correct or incorrect can be exploited to gain knowledge, however small, of the password in less time than would otherwise be the case.)

The delay is an artificial delay to make repeatedly trying to gain access by using different passwords infeasible, even if you have some idea of what the password likely is and automatic account lockout is disabled (which it should be in most scenarios, as it would otherwise allow for a trivial denial of service against an arbitrary account).

The general term for this behavior is tarpitting. While the Wikipedia article talks more about network service tarpitting, the concept is generic. The Old New Thing isn't an official source either, but Why does it take longer to reject an invalid password than to accept a valid one? does talk about this near the end of the article.