slowing down while rendering

[zilberdik]

why if im turning off LOw batch rendering and batch redner also off
each time i render the computer get slowed down and i my win 7 get almost stuck until render finishes

my vray ver. is 1.48.94

my system is q2 quad q6700 2.66Ghz
8 GB RAM

Windows 7 ultimate

* the renders arent big and the scene is a rather regular inteerior

10x