i have 3 nec 3520 16x burners, if I burn one drive it's done in 6 min. all 3 drives do this. if I burn 3 at a time it takes 15 min. when I had 3 nec 2500 4x burners it only took me 14 1/2 min at 4x to do 3. If i do 2 at a time it now takes like 13 min. The green lights on the burners are not staying on all the time either. I thought it might be a memory problem but i put a gig in it and the same thing happens. Please help.