Is possible elinate lags???

hello, please, my lg g3 d855 16 and another mine 32gb, are full of lags.... i used every stock rom, now 20u, every modded rom but this problem doesn't eliminate. before i sell this phone i ask more expert users for tell me is with cyanogen rom (i never used) i solve this problem, in case negative i must sell these phones very beautiful but lagging.... please what can i do? thanks to all !!!!