NOTE: i don´t speak english.

minecraft are lag problems in singleplayer and lan:
references:
tps: ticks per second

*default worlds:
*singleplayer:
default worlds are a very big amount of lag (0.5 to 10 tps)
passed a time the tps are normalized
*in lan:
default worlds in lan are a very big amount of "inverse lag" (20 to 30 tps)
passed a time is not tested

*superflat worlds:
the tps in this type of worlds are perfect (20 tps)