Following this page,
https://docs.nvidia.com/video-technologies/video-codec-sdk/12.0/ffmpeg-with-nvidia-gpu/index.html
the following encoding went at around 21 fps with the NVidia 1060 graphics card -
ffmpeg -r30 -start_number -003875 -f image2 -i "OpenSpace%06d.png" -c:v h264_nvenc ../filename.mp4
Using h265_nvenc gave codec not found error, but hevc_nvenc worked. That went at around 23 fps. Without acceleration, when using the "lossless" parameter, it was taking several seconds per frame. 0.2 fps or so.
