Please, check the version explicitly with 'growisofs -version'. I [for one] don't keep track on which version is shipped with any particular distro or when updated. If it's less than 5.19 (as mentioned at http://fy.chalmers.se/~appro/linux/DVD+RW/hcn.hml), then update. If not, submit the actual dvd+rw-mediainfo output for the media in question.ok, the problem got worse when i upgraded to 5.21. now growisofs changes the write speed to 8x, but the actual writing of the disk tops out at 2.5x.
Is it possible that DMA was on by then, but not now anymore? Then keep in mind that if you set recording velocity to value higher than your system can sustain, then resulting *actual* or *effective* speed doesn't flat out at the latter value, but on some value *lower* than that. And depending on firmware implementation it can apparently drop down *dramatically*. In other words if your system for example can manage only 6x [for whatever reason, which most likely will end up beyond the scope of this discussion] and you make unit record at 8x velocity, the resulting *effective* speed might as well be 2.5x. That's because unit will have to take idle revolutions... For optimal performance [and recording results] you should choose recording speed just a bit lower than your system can deliver. A.