Grass block causing high server load

Here's what my warmroast is showing with 450 players online on my creative server: http://i.imgur.com/ca0EbHR.png
http://i.imgur.com/T6gkdu9.png
For some reason the chunk resources also seem high even after the recent patch but that may just be me (I'm not sure if it's normal?) I never had this issue with 1.8 leading me to think it's a 1.9 issue possibly related to chunks? My plots are each 516x516 and the top layer is made out of grass blocks so I suspect that there is some relation between the chunks and grass block timings because grass blocks have no reason to cause such bad timings.