Lag issues pls help

[ShizukuChan]

my blade and soul keep crashing/perma screen freeze almost every 15-30mins my laptop juz keep getting laggier and laggier till it crash and i do not know the problem. always when i juz restart the game it will be very smooth for the first 10mins  but once it lag it juz keep getting worse and does not get better. my auto graphics is 4 and i think my laptop should be able to handle this game pls help me >_<.

laptop specs:

Processor:intel(R) Core(TM) i7-4720HQ CPU@ 2.60GHz 2.60GHz

RAM:16GB

GPU:NVIDA GEFORCE GTX 960M 2GB

C DRIVE: 2GB OUT OF 43.1GB FREE (was wondering if this was the cause)

D DRIVE: 890GB OUT OF 931GB FREE