The office DVDROM loves the 2x burned Sky DVD-R Disc

I am cataloging a Sky 4x DVD-R disc (burned at with with 2x speed) full of photos using Porfolio 7, and I found out that the catalog process went very smooth. In fact, a bit smoother than I expected. I don't know if it's because of the DVD-R disc burned right, or that the catalog file itself is resonable small as of now (about 800Mb).