The recording speed in RTX Mode will largely depend on the power of your graphics card and the resolution of the 3D view.
If you want to render RTX Mode faster, try using a newer Nvidia card, such as the new 40 Series. This will cause each frame to render faster, which will reduce the overall time required to record.
You could also consider recording at a low resolution and then using AI video upscaling software to increase the resolution of the final video. Using AI to upscale the final image of each frame may be faster than calculating each of those pixels in RTX Mode. Upscaling software may also be able to interpolate frames into the video so that you can capture at a lower framerate. Whether that would be faster than calculating each frame during recording is hard to say.
Phil BoBo
Sr. Manager, Software Development