@Filyps You laptop is probably seeing and using both the 3080 gpu and the 680M gpu... I would guess optimal setup in Vegas would be to select the 3080 in video prefs as the main gpu and the 680M in i/o prefs for decoding. That would require that both Nvidia & Amd drivers be installed. Look and see.

A similar optimal config for the desktop would be to configure Vegas to use the 3070 as the main gpu as well as in i/o prefs. Unfortunately the 14700KF has no igpu making it less powerful than the 14700K would be for editing video. I think those 2 cpus fit the same socket so switching might be the most economical way to fix the situation. If you did that and installed Intel graphics drivers, you could set Vegas to use the uhd770 igpu in i/o prefs which should make a tremendous difference.

Can you show the result of Help/Check for Driver Updates on the desktop ?

I checked and everything is up to date. I also checked it with ccleaner and it detected only things like wireless and few detail drivers updates.

@Filyps You laptop is probably seeing and using both the 3080 gpu and the 680M gpu... I would guess optimal setup in Vegas would be to select the 3080 in video prefs as the main gpu and the 680M in i/o prefs for decoding. That would require that both Nvidia & Amd drivers be installed. Look and see.

A similar optimal config for the desktop would be to configure Vegas to use the 3070 as the main gpu as well as in i/o prefs. Unfortunately the 14700KF has no igpu making it less powerful than the 14700K would be for editing video. I think those 2 cpus fit the same socket so switching might be the most economical way to fix the situation. If you did that and installed Intel graphics drivers, you could set Vegas to use the uhd770 igpu in i/o prefs which should make a tremendous difference.

Maybe I didn't write clear, but I don't use the notebook anymore. I am not sure what 680M and 3070 refers to.
How could I switch them? I only see the "Optimal - 4070" option in vegas and I can't install graphics drivers for intel core i7 (it displays error that no gear for the drivers was found)
 

Thank you for investigating.
I started thinking that it's because vegas 19 is not supporting this GPU but I just tried rendering project on Vegas 21 trial and it is still the same.

Try the benchmarks in my signature and see how they compare to other users with similar hardware.

He meant 4070 not 3070 for your desktop.
Your KF CPU has no Intel iGPU- he was suggesting selling your CPU and getting a K one which does have an iGPU.
The AMD Ryzen 9 6900HX has a Radeon 680M integrated GPU.

Try the benchmarks in my signature and see how they compare to other users with similar hardware.

He meant 4070 not 3070 for your desktop.
Your KF CPU has no Intel iGPU- he was suggesting selling your CPU and getting a K one which does have an iGPU.
The AMD Ryzen 9 6900HX has a Radeon 680M integrated GPU.

I tried the benchmark and it took 1m 08sec to render the 4k sample (with the same settings as in the instructions)
Oh, what a failure, KF and K is difference of a few dolars .
This gear is fresh buy, I would like to avoid changing it. So the Vegas is not using the nvidia gpu at all?

Your results are totally fine. You are about #31 for UHD renders and your preview framerate (16) confirms that it is using the NVIDIA GPU.

If you put dynamic ram preview back to the default you'd likely score significantly better. 0 can kill performance; the only reason to set it to that is if you see render glitches (which VP 19 fixed to a good extent).

The K vs non-K is beneficial with some media as Intel decoding is quite good. The media this project uses is basic AVC so there isn't likely much difference between QSV and NVDEC here. If you find yourself using a lot of media that Intel excels at (say HEVC 10-bit 4:2:2) you could add the cheapest ARC card and use it for decoding with the NVIDIA doing the timeline and Fx. Either can do rendering (encoding).

Thank you for clarification.

Well it turned out that the big render time difference is result of adding the new animated text patterns (I replaced old text patters with new one when I moved project to the desktop) I didn't expect this media generators to be so heavy, it's just a second of animation and then still text, but it seems it's consuming a lot of render time.