Most Minecraft server's do this, Some things to do is, Limmit server connections, Limmit maps, limmit the ammount of Physics. Stuff like that will now cause AS much but will hog the mem.
I've just checked it, there's no reason for surge in CPU use. Actually it's other way round, the new versions are faster than the previous. You can perform a test to be sure, compare with the older release -> download/MCDziennyLava5.9.rar