Hi there

If you getting any crashes with Nvidia drivers, try raise TDR as per this article

https://docs.substance3d.com/spdoc/gpu-drivers-crash-with-long-computations-128745489.html

Yes you should be seeing OptiX with Windows 10, not sure with Win7, I have only Win10 installed there, can you please check drivers if you are using latest drivers?

Hope this helps

Thanks, Jura