Write speeds are determined by a couple of factors. The primary one is the write strategy employed by the writer; this is based on the mediacode of a given disc you insert into it. So Brand-X may give that, Brand-Y may say 2x, 4x, 8x, 12x, 16x --- like that. Verbatim, Taiyo Yuden, and Ritek G05 are recommended media to use --- higher quality media and with excellent longevity. DVD-R over DVD+R (technically it'd work in a pinch, but -R if at all possible).