How does Avidemux uses Nvidia encoding a lot more efficiently ?

[pulsarstar]

This is more a question out of curiosity than a necessity to know.
When using Nvidia HEVC or Nvidia H264 encoder why does Avidemux use a lot more processing power from Nvidia Chip than other software, that uses the same method, supposedly?.
Example encoding a video in
2160P film it uses 50% + power .
I can encode the above movie in 5 minutes.
Where many other programs that use the same method only use 4% of power of Nvidia GPU.
And it takes hours to process the same video.
Percentages were gathered from using Windows 10 Task Manager> Performance>GPU 0 Nvidia Geforce GTX  51%..........4%
I can guess, and speculate why Avidemux is much better but
I would like an answer from somebody who is more in the know?
Thanks.

[eumagga0x2a]

I suppose that "other software, that uses the same method" simply doesn't use the same method, i.e. doesn't use dedicated units in the graphics card to compress video but performs the encoding on the CPU.

can encode the above movie in 5 minutes.
Where many other programs that use the same method only use 4% of power of Nvidia GPU.
And it takes hours to process the same video.

You can massively slow down NVENC-based encoders in Avidemux by adding computationally expensive video filters*, if you wish so :-)

*) so that not encoding but filtering becomes the bottleneck.

[pulsarstar]

Thank you, eumagga0x2a
for your thoughts on the subject.
I came to the conclusion that Avidemux
must be programmed/coded better.
Avidemux is faster at encoding,
at lot faster!
& the output quality looks better,
on viewing on the TV.