Measuring laser lens power at different read/write speeds?

Because I hate saying “the title says it all, already”, I will explain it more detailed:

  • How can the power of the laser lens (mW, voltage, ampèrage) be measured?
  • Is the power any different at different speeds of reading and writing? Is it higher at

higher writing speeds? Also for reading?

  • How much is the approximate power of different disc types at different speeds?
  • Is it the same for all drives on the same disc type?

Advanced features of Nero Burning ROM worth paying for?

In your opinion, is it worthed to purchase Nero’s software?

Is it necessary to pay for a burning software, or is CD-Burner-XP (works with Vista too) and

InfraRecorder (cross-platform, open-source) and ImgBurn sufficiently good?