Constant freezing when gaming/watching videos

[ManOnWire]

I recently was gifted this homebuilt pc by my fiance...
CPU: Intel Core i5 2500k
RAM: 8GB ddr3 (2x4)
Mobo: ASUS Sabertooth P67 B3 rev
GPU: EVGA GTX 580
HDD: WD Caviar Black 1tb
PS: Corsair Professional HX 850w

When gaming/watching videos the system often will freeze for >1 second - the sound and graphics cut out. Then it continues to mow along as per usual. What could be causing this - at times it's incredibly debilitating for gaming? Thanks in advance!

 

[kichu9193]

this will b due to any unhandled process which works on the system background check the task manager and kill the process which makes pblm......the other reason will b in asus motherboard we can increase the graphic memory sometimes the memory value will b set to low so it will b taking a sec time delay...try increasing it frm the bios

 

[ManOnWire]

Can someone maybe expand on what kichu said - or have any further guidance for me?