At 8x speed these blanks were fired but without problems and without errors. I had ordered a total of 100 blanks and all 100 were burnt by me error free. At 8x speed to burn a full DVD takes about the 8min and that's enough. One should also consider that the 16x speed can only be used at the last 300 MB and thus brings no big speed advantages.
Although these blanks have compatibility issues with 16x speed, you can buy them quiet, as you so be certain that you could also write at 16x.