Talk:Janna/Strategy/@comment-201.255.152.99-20120218200003/@comment-184.174.138.68-20120407014617

Well, movement speed has DR.

At 415 movement speed, any additional points have 80% effectiveness. For example, if you have 450 movement speed from items, you will get a REAL movement speed of (450-415)*0.8 + 415 = 443. If you exceed 500, the DR goes from 80 to 50%. So if you were to go crazy and put quints, masteries, and boots of mobility (310 + 130)*1.285 = 565.4

So you actually get (565.4-500)*0.5 + (500-415)*0.8 + 415 = 515

That's still pretty damn fast, but you lost a sizeable chunk of efficiency that could have been used much better for survivability or thoroughput. You already move through units as Janna, so it's not like you need to outmanuever them as much as say Yi when escaping or chasing for the kill.

So for swiftness boots, you gain 20 more base movement speed that suffers from DR at the cost of 15 CDR which you will cap as support, which translates into less armor, MR, or maybe ap. That's one reason why swiftness is not popular in general. +20 base speed is not worth it for a lot of people.