Solved Question about rendering video with Nvidia GPU and Magix AVC encoder

Hi there, just a few details to start with.
On my new PC I have a Ryzen 1700x processor, a Nvidia GeForce GTX 1060 6GB graphics card and 32 GB of memory.
I have just completed a 1 hour project with source video which is HD 1920x1080 mp4 at an average of 25 Mbps. I have now rendered this to various formats and as a result I have a few questions which I hope someone is able to answer.
First render was using the MAGIXAVC/AAC MP4 Format and Internet HD 1080p 50fps (Nvidia NVENC) template. All was fine and the render took about 45 minutes, which I believe is excellent. My previous PC would have taken at least 2 or 3 hours or more.
Second render was the same format but using the Blu-ray 1920x1080-50i, 25 Mbps video stream. This also was fine and completed in 46 minutes. Again excellent.
For both these renders I had the following settings:
In options, preferences general tab, Allow legacy GPU rendering was off.
In the video tab, GPU acceleration of video processing was set to NVIDI Corporation (GeForce GTX 1060 6GB).
Now to the problems:
I then tried to render to DVD format using the GeForce GTX 1060 enabled. I used the MainConceptMPEG-2 Format and the DVD Architect PAL Widescreen video stream template. I tried this many times but at several stages the rendering just froze and stopped. I then reset by setting GPU acceleration of video processing in the video tab to off. The render then worked fine and completed in 55 minutes.
So I then rendered again using the MAGIX AVC/AAC MP4 format and the Internet HD 1080p 50fps (Nvidia NVENC) template but this time with GPU acceleration turned off. The render was fine and I was surprised to see there was no increase in time, again 45 minutes.

So the question is why is this happening. I thought the GTX 1060 card would help significantly with rendering times in all formats but it appears it does not reduce rendering time and in the case of DVD stopped working.
When editing on the timeline with several video tracks, some colour correction, stabilisation etc. the graphics card helps greatly with the video preview. In the past I set this to Preview Auto, but now I can set it to Good Full and it previews fine.

Finally just a few more related questions while here:
When rendering to MAGIX AVC/AAC MP4 and the Internet HD 1080p 50fps (Nvidia NVENC) template, I can customise the template as follows:
Encode mode is set to NV Encoder rather than MainConcept AVC.
NVENC Preset is set to default but there are several other options, so any suggestions here?
NVENC RC Mode is set to VBR. Again there are other options so any suggestions would be appreciated.

I think that is it for now and I apologies for the lengthy detail. I have now found out how to render to the various formats but it would be good to know why I had the problems and perhaps get answers to my questions. I like to know why things do not work even if I have now found a solution.

I appreciate your time and all the help I receive from members of this forum.

Regards and best wishes
BobH

Hi Bob

I am still using a Legacy Nvidia GTX 570 graphics card, so I am unable to test NVENC encoding.
Another forum member who is using a modern Nvidia GPU, should be able to help.

Not all render output formats support GPU Acceleration.
Magix AVC encoding is specifically designed to take advantage of modern Nvidia Graphics Cards.
Older output formats do not support modern Nvidia Graphics Cards.

I always render video for DVD or Blu-ray using Mainconcept MPEG-2 format.
I don't know the reason why, but you should always turn your GPU off, before rendering to Mainconcept MPEG-2 format.
Leaving your GPU turned on, will cause the render to fail.
This problem is in many different versions of Vegas Pro and Vegas Movie Studio Platinum.
I have no idea what causes this.