freezing while playing

[tuga005]

I don't know why but my computer keeps freezing while playing some games like, sniper ghost warrior 2, tomb raider e mass effect 2. While it freezes i can't do nothing, the system don't respond to my commands and to pass this i have to press and hold the star buttom, sometimes the blue screen appear. Some says i have do decrease the ram frequency but how i do that?

PC Specs:
intel pentium g3258 dual core 3.20ghz
gtx 750 ti
8gb (2x4) kingston 1600mhz
windows 7 home premium x64

P.S: Has i use the cpu-z it shows that the memory speed was 1440.

 

[Zxjamesxz]

Do you know how to enter your BIOS? Depending on your motheboard, you will have to press a key on startup, and you will be shown settings for things like your CPU and RAM, etc. Go into the RAM clock speed and set it manually for 1600mhz.