Why you guys don t work on making sony vegas lighter ??

I would recommend you contact the new owners of the Vegas editing package and their name is Magix and you can find them at Magix.com. Based on what I have seen in using this software, if your computer is adequately equipped to handle video editing, then this software should not tax your computer. Does your computer meet their minimum hardware recommendations? How new is your computer? I have been using Vegas since it was Version 7 about 15 years ago. I think the best answer for you is to focus on how you can help your computer to keep up with the changes in software.