– Dynamic RAM preview max back to the default of ‘200’. You only need to increase this in the event you are Building a Dynamic RAM Preview. NOTE: If your playback Preview does not improve you could also set this to zero just as a test.
– Set ‘GPU acceleration of video processing:’ to ‘Off’ (will need to restart Vegas). Does this help?
– Right clip on the Preview display. From the options is ‘Adjust size and quality Optimal Playback’ checked? If so un-check this option. Does this help?
– Close Vegas, reboot your computer. Do not start any other programs. Start Vegas Pro, new project, add only one of your ProRes source clips and bring that to a track on the timeline. Does this clip (event) run smoothly with the Preview set for ‘Good’ or ‘Best’?
– Where is the source ProRes from, a camera or screen capture, or something else? Can you post a screenshot of the source media specs using the free Mediainfo app set in text mode?
– You may also want to perform a full reset of Vegas, hold down the ‘Ctrl+Shift’ keys and double left click on the Vegas Pro desktop icon. Check the bos ‘Delete all cached application data’, then left click on ‘Yes’. This will rest Vegas Pro to it’s installation default settings and delete the pesky cached application data, which over time accumulates and sometimes causes Vegas to do strange things. In this case most likely will not help.
Will wait for you reply to this for further ideas. I can tell you I have a much less powerful PC than yours and I work with PorRes HQ 422 10 bit and DNxHD/HR 422 10 bit source media and can get reasonable playback speed (usually full speed with color correction, LUT’s and transitions) at Best/Full or at least Good/Full.
Best Regards……George