15 seconds for 3 minutes is quite slow, the open source thing i use, spleeter, says 100x speedup over realtime with a GPU, that would be 1.8 seconds for three minutes, which means that spleeter could, in fact, given all of the arguments of what i asked, do it "realtime".
It depends on the hardware. The laptop I use for DJ doesn't have a dedicated GPU.
I also use open source, preferring demucs over spleeter.
In my experience spleeter requires huge amounts of memory, my DJ laptop only has 16GB of RAM, and I need to close the browser to be able to successfully stem a 5 minutes song.
Demucs takes a bit longer, but it uses just 2GB of RAM. And the sound quality of the stems separation is much better with demucs, which is a more important factor than the runtime, IMO.
