So, just because I'm on a coffee rush, I'll speed this up;

1.) I start new game,
2.) I go get Chance's Knife,
3.) IT'S FREAKING BEASTLY NOW.

I can slash it at like an average of 5 times a second all of a sudden! I don't even have the required melee skill for it yet! Was this just because of the new update, or has my game finally given in to me and given me god-powers?

No its attack per second is about 4 the vault says 4.15. If you get all the perks that would affect it, you could almost swing it 6 times as it goes 5.81.