The Jarvan IV picture is from PBE, Vi's picture is from live. I assure you, both pics were taken in base without homeguard, or any speed increases mastery/runes.

J4's base movespeed is 340. 439-340= 99 increase in ms
Vi's base ms is 350. 447-350= 97 increase in ms

PS- Love the new J4 Skin (:

Attached Thumbnails

 

http://euw.leagueoflegends.com/board...read.php?t=228

Q: What are these diminishing movement returns? (Credit to Guinsoo)

A: For each point of movement you would have above 490, that amount is reduced by 50%. So if your final movement speed was 748, it would be reduced to 490 + (748-490)*0.5 = 604. For each point of movement you would have above 415, it is reduced by 20%. So if your speed after all mods was 445, you would end with 415 + 30 * 0.8 = 439.