Do you mean on stories? I've noticed upvotes on stories don't give you 1 karma each, it's less. Not sure if it's a linear 0.5. But upvotes on comments seem to be 1 each.
Both modulo moderation, of course.
Occasionally, though, I have this post that gets a decent amount of upvotes but not a single comment. I never understood why. I post for the comments and not for the upvotes. It is very frustrating, especially since it is a miracle to me what distinguishes these posts from the popular ones.
Capping the points on these makes a lot of sense though. In the end they don't contribute much.
https://meta.wikimedia.org/wiki/Cunningham%27s_Law
>Cunningham's Law states "the best way to get the right answer on the internet is not to ask a question; it's to post the wrong answer."