rendering: source files or program files disk used?

Hi there! In order to decide the type (SSD or HDD) and storage capacity of new disk I need to know where Adobe programs do the rendering (if all programs perform the same way e.g. Illustrator and Premiere) Assuming we have two different disks: the rendering uses the disk where the source files are stored or the disk where the program files are installed? Let me pose the question in a different way: if source files are stored in a HDD and the program is installed on an SSD will the rendering be slower compared to an SSD storage? Thank you.