Problem With My S4 i9500

Im having Problem with my s4, im using custom rom S6/S6 Edge v3. Before that im using cm12.1 . that i have problem with the phne which it's. it become lagging and the apps become crash without notice a problem. Now im using s6/s6 edge rom still have that problem, so how to overcome the problem. TQ
#SorryForMyBadEnglish.