Slow Ticks on Empty World

Im building a skyblock remake so to start an empty world i have tried creating a world with just air (2;0;1 in presets), I have tried downloading a map online and tried the 1.6 locked chest thing but in all versions the ticks are slow as in i move fast and if i press q the item falls at normal speed but on creating an entity (Spawn eggs and /summon)
if i punch them or they fall the keep lagging every half block also redstone ticks are much slower
Steps To Reproduce
1. create an empty world
2. spawn a mob
3. punch it, it will fly back slowly
4. use an ordinary redstone clock doing something like tp you will see it will tp very slowly