EDIT: Ooops, I should have put this an ala42's thread. Sorry!
I have a stack of 4x KHypermedia -Rs (CMC AF1) that I've been trying to get through. I tend to burn other media most of the time because it's faster. So I figured I'd try swapping strats and see how this media likes overspeeding. I swapped the strat for AF1 with the strat for CMC AM1, which apparently is 16X -R media, and tried some burns. Here are some results!
1. Burned at 4x with B7P9
2. Burned at 16x... scan ended with "no additional sense information"
3. Burned at 12x... same result, got further though
4. Burned at 8x... again, same result, further on though
Conclusion... looks like it's best to stay at 4x with this media.