my new asus r9270x ddr5 graphic card hangs my pc some this it seem like it stops working

Umang Rathi

Honorable
Dec 15, 2013
4
0
10,510
hi,
I just purchased a new pc
config
AMD FX 9590 PROCESSOR CPU
CORSAIR VENGEANCE DDR 3 8GB (2X8UB) ram
ASUS SABERTOOTH 990FX R20MB MOTHOER BOARD
asus r9270x ddr5 2gb graphic card
COOLER MASTER SEIDON 120V PLUS COOLER FAN

with this configuration when I am working on pc after 2-3 hours it start getting freezed ,every thing stucks , nothing is working and i have to forcefully restart pc. and after restarting it works gud but the display become quite pixelet not to much but just little.
I purchased it only a week ago

please help