I read thread after thread about people not being able to see their Nvidia graphics card in Vegas' preferences.
I was having the exact same issue, with my 750ti.
I was able to fix the issue, but it wasn't because I saw the answer in any of those threads (or I didn't realize it).
I have Windows 10 and I got drivers through Windows Update.
Those drivers contained the control panel, desktop right-click menu entry, etc...
It seemed like everything was right.
I went to Nvidia's website, downloaded/installed their latest drivers, and rebooted.
The next time I fired up Vegas, I had GPU acceleration enabled!!!
Apparently, the issue was the drivers that Microsoft was pushing down.
I don't know if they were just too old or if the OpenCL stuff was removed.
Regardless, these drivers made it work...
Version 364.51 - WHQL
Release Date Tue Mar 08, 2016
Operating System Windows 10 64-bit
Language English (US)
File Size 324.91 MB
Obviously, I'm not looking for assistance.
Hopefully, this answer will help someone else.
Thanks for sharing that and there is a good lesson to be learned. I would never use a driver from Windows Update. Always use either a driver from the card manufacturer (ASUS, Gigabyte. MSI, EVGA, etc.) or from the NVDIA or AMD site.