I'm using Vegas Movie Studio Platinum 17 (Build 179) with default settings with the exception of adjusting the Dynamic RAM Preview and the maximum number of rendering threads (I'm a long-time Vegas user, so I know how to properly set these basic settings). I'm using Windows 10 with a Nvidia RTX 2070 Super and all drivers are up to date. Part of why I upgraded to 17 is so I could use the RTX card to enhance encoding/decoding and to be able to render HEVC video with NVENC acceleration. Most of the time, rendering fails immediately, rendering between 0 and 5 frames before the program completely freezes and has to be killed with the Task Manager. Sometimes it renders roughly half of the project before freezing, but this gives me an accurate idea of how long the project would take to render. This is true for all rendering options, regardless of resolution, frame rate, hardware acceleration, etc. However, if I check the "Enable legacy AVC decoding" option on the File I/O tab, everything renders fine. Problem is, this changes the hardware decoder from Nvidia to Off and the video takes roughly 25% longer to render.
I haven't found anyone anywhere on the internet with this specific problem. Any ideas as to why this is and how to fix it?