Ableton Forum

Hello,

I am a big fan of stem separation, I do it all the time. I was on Sonoma and the separation performed super fast. Yesterday I updated to Sequoia, because 2 softwares were incompatible with Sonoma.

Now the stem separation is ultra long ! I mean at least 10 times slower. And before you tell me, YES I was using the High Quality setting in Sonoma.

Do you notice Performance issues with Sequoia ?

There was a known issue with (very slow) stem separation in Tahoe, but it' supposed to be good since Apple fixed it with this week's update.
But afaik there was never any issue with older macOS versions.

Ok, I figured it out.

My stereo track was 43 minutes long, I only separated a 2 minutes segment. BUT in the backend, Stem Separation separated the whole 43 minutes long (just showing me the 2 minutes)

It was only when I edited that 2 minutes that I noticed it separated the whole thing.

Next time I will conolidate before doing stem separation

[jur] wrote: ↑

Sat Jan 31, 2026 12:26 pm

There was a known issue with (very slow) stem separation in Tahoe, but it's supposed to be good since Apple fixed it with this week's update.
But afaik there was never any issue with older macOS versions.

As for Tahoe, I'm on the latest version 26.3 (25D5112c), but in Live 12.3.5, I still get the message about separation not working in Tahoe 26.1. Separation is indeed slow. So this check and message appear to be hard-coded rather than verifying if macOS components are available. Do you know if this is true? If Live is actually verifying, it's still not working properly in Tahoe (at least in my case).

Ok, my bad, I just checked and:
macOS 26.3 Beta (25D5112c) fixed whatever regression that caused the issue with stem separation, BUT Ableton now needs to re-enable GPU processing for stem separation on machines running this OS.
TLDR, it should be fixed with the next Live update.

Slightly offtopic but is there GPU-assisted stem separation on Intel Macs?

On my 2019 Mac Pro it's quiet fast but runs on the CPU only.
Would be cool having it on the GPU as the Mac Pro supports very fast GPUs and even Multi-GPUs.

benmuetsch wrote: ↑

Mon Feb 02, 2026 11:24 am

Slightly offtopic but is there GPU-assisted stem separation on Intel Macs?

Nope.

benmuetsch wrote: ↑

Mon Feb 02, 2026 11:24 am

Slightly offtopic but is there GPU-assisted stem separation on Intel Macs?

On my 2019 Mac Pro it's quiet fast but runs on the CPU only.
Would be cool having it on the GPU as the Mac Pro supports very fast GPUs and even Multi-GPUs.

Yes. In the Beta i read that they added this as far as they say.
But ONLY for Tahoe. I am on Sequoia so no joy….

From 12.4b8 Release notes:
Lass paragraph of „Bugfixes“

"Stem separation can now use the GPU instead of the CPU on computers
running macOS 26.3, which makes the separation process faster."

I guess that's only for Apple Silicon.. there will be no real (feature) development anymore for Intel based Macs.