Well i found out that some servers are laggy with even 5 players so i decided to start making blog about tips how to improve your server performance sadly i made tips only for papermc software so if you want to motivate me about that leave something 
Paper-World-defaults.yml
Basic : anti-xray:
enabled: false
Optimized : anti-xray:
enabled: false
Impact (Minor)
If set to true server will hide ores from players what are using x ray
Basic : engine-mode: 1
Optimized : engine-mode: 1
Impact (Minor)
If you have x ray enabled there is 2 engines modes Example : Anti-Xray Engine Modes but if you want your server less lagy don't use anit xray option
Basic : keep-spawn-loaded: true
Optimized : keep-spawn-loaded: false
Impact (Medium)
This keeps spawn always loaded if you don't want to disable this u can change keep-spawn-loaded-range: 8 to lower values
Basic : delay-chunk-unloads-by: 10s
Optimized : delay-chunk-unloads-by: 6s
Impact (Medium)
Delays chunk unloads by the specified time
Basic : entity-per-chunk-save-limit:
arrow: -1
ender_pearl: -1
experience_orb: -1
fireball: -1
small_fireball: -1
snowball: -1
Optimized : entity-per-chunk-save-limit:
arrow: 10
ender_pearl: 10
experience_orb: 10
fireball: 10
small_fireball: 10
snowball: 10
Impact (Medium)
That depends on how much items will be saved per chunk for big servers u should set that to any value between 10 - 30 in order to decrease lag
You can find more about that there http://opt.pickaxe.tk
