Hello,
Not sure if you found a solution to this, but I think I have.
I looked at the posts of hacks to get unsupported cards working in adobe premier cs5, and oddly enough following steps 2 and onwards from this: https://blog.krama.tv/hacking-adobe-premiere-cs5-to-enable-more-nvidia-cuda-cards/ works!
I monitored my graphics card with msi afterburner and it shows it using 30% gpu usage while previewing video.
Anyway seeing as this was the only site that came up when I googled for a solution, I thought I’d let you know what I’d found.
Cheers,
James