Thanks for the answers,
If one uses QSuite, it is recommended always as a write speed 4x for the TY.
Also I see a clear difference between 4x and 8x writing speed with the TY.
A new firmware will probably solve the problem.
It is funny, only if I use Record Now, the drive does not throttle the burning speed.
It happens always only in ImgBurn (therefore my question).
If the new version of ImgBurn is available, I try it over again.
Thanks!