Premiere Pro did not have an internal Nvenc encoder, only 3rd party that have been around for years. The integrated Nvenc support is much better though. That is difference between VegasPro and Premiere, When using Voukoder on Vegas it's faster than integrated Nvenc encoder, but with Premiere integrated Nvenc looks to be twice as fast as Voukoder nvenc (limited testing) and may be as fast as Davinci Resolve now (have not seen a comparision yet)

with Premiere integrated Nvenc looks to be twice as fast as Voukoder nvenc (limited testing)

Both with their default settings of with the similar settings?

Yes, can't you see it in Vegas Pro render templates?

off course, but I do remember someone said used voukoder (as what lenard-p said) to fully use the NVENC encoding,.

This is the encoding comparison.

In YT description he links to another video with templates he uses at 2m15s

I do not know much about NVEnc, but in the comparison he used different options for Voukoder/NVEnc vs Premier/NVEnc.

Voukoder NVEnc: fast, cq 15, rc-lookahead=16, bf=3

Pr/NVEnc: VBR, 1 pass, 50 Mbps - 300 Mbps

In media info of resulting files Voukoder/NVEnc -- 2 Ref frames, Pr/NVEnc - 1 Ref frames

No information about B frames in media info and it is not possible to check if B-frames were used or not used in every case.

Anyway, encoding options are very different and it does not make sense to compare encoding time, quality, file sizes in such situation (btw, Voukoder/NVEnc 1.5 times smaller, Voukoder/x264 -- 4 times smaller).

I think removing rc-lookahead and bf from Voukoder/NVEnc options will make encoding times close to Pr/NVEnc.

Still, Pr/NVEnc with the same settings should be a bit faster as lower overhead. But not two times faster.