Nero has a link touting the advantage of Recode over the competitors. I don't know if PSNR is a log function. I suspect that it is not. From these tests, Recode's number is better than Clone DVD by 822 PSNR. If this comparison is linear, then then improvement is only about 2.2%. Also note that there is virtually no difference in PSNR between Recode Fast mode and Recode High quality mode.