DDJ-RB Distortion while using the build in PC speakers

I've recently bought the Pioneer DDJ-RB, extrimelly happy with it so far but I've got one issue, when the pionner is connected to the PC and i'm using the PC's speakers after about 10-15min of playing the distortion appears, I've changed the buffer size but it's only allowing me to play without any distortion for 5-10min more. I've read other posts about it any havent found any solution to it, how can I fix this error ? 

Thanks for your help !