A while back, else-net, I was discussing CD-R with some people I know in the music business. Apparently, writing CD data at high speed is more likely to lead to read problems. The laser doesn't go from 0 to 100 in zero time, and the high-speed write burns a fuzzy-edged mark, For something to work reliably in older audio-CD readers, you have to burn slow. Which is frustrating for people with lots of data. Anyway, it may be worth holding back on the write speed. The modern drives can switch the laser more rapidly, but the top write-speed is still pushing the limits.