This has been explained multiple times on this forum. SL12 unmix modules are “better” and therefore take much longer to process.
I, personally, tested some unmix differences between SL11 and 12. I found the drum separation from unmix song to be better in my testing.
That said, I have little use (if at all) for unmixing of music in daily tasks. I use unmix noisy speech much more often (all the time) and UNS is definitely better in SL12 than in SL11 in my tests.
Yet, that is my experience and there are claims of all types on this board.
You are correct and thanks for letting me know. I did already know that and I’m aware of the explanations / possible solutions.
My comment was from the point of view of practical usability. Based on the comments in this thread, on some systems the differences between 11 and 12 are radical and on occasion may render 12 virtually unusable for certain functions. It’s not unusual for users to be surprised by this… since the expectation might be for a user to carry on in 12 from where they left off in 11. Claims that quality is better in 12 are without doubt legitimate but do not preclude practical performance issues. A user can always go back to 11 for certain functions but this could be considered a ‘cop out’. Just saying and not trying to score points here.
For what it’s worth… for the same original recording, I agree that SL12 extracts the drums much better than previous versions. Extracting vocals is sometimes better and sometimes worse. However, guitar and especially bass guitar are generally worse for me. I am extracting stems from simple stereo recordings of my band practices from 10-15 years ago - so they are not multi-track studio recordings by any means.
I had originally used unmix songs from SL10, then SL11 and now SL12 for each song recorded and in each case I have selected the best stem - which might come from any of the SL versions. I guess I will try again when SL13 comes out in the hope of improvements. This is becoming somewhat tedious though since each new SL version certainly does not guarantee improvement for a particular stem - so in my case all must be tried.
Speed is not really an issue for me as I am retired and not doing this professionally, although faster would be appreciated. I would rather have better quality, even if it took longer.
I hope SL 13 will improve across the board though - fingers crossed!
SL12 can be much slower if it’s not using the GPU. Check your settings and re-enable GPU processing—SL12 may import SL11 settings but defaults to CPU until GPU is properly set. High/Extreme modes rely heavily on GPU, so processing times drop drastically once that’s fixed.