also,i'm having very unstable writing speeds,when burning at 4x,it stays at 4x most of the time but sometimes go back to as low as 2,7x,and even went back to 0,0x once then back up to 4,0x,what could be causing this,cuz i suppose this isn't normal,especially the going down to 0,0x? My drive isn't fragmented and nothing is running in the background...