I'm wondering if i run the "correct" version for my M1 studio.

I have installed the production build 19.5.605 Intel Mac (which obviously isn't for m1 as it seems), and the daily build 19.5.633. I cannot see any other version in the launcher which indicates an apple silicon build.

As my UI is responding kinda laggy, and the renders aren't that quick, i get the feeling i'm not using the most optimised version. Which version do i need for optimal performance?

Have you installed the launcher for apple silicon?
https://www.sidefx.com/download/ [www.sidefx.com]

When you download manualy then look for the arm64 build and NOT x64 or intel build.

mandrake0
When you download manualy then look for the arm64 build and NOT x64 or intel build.

I'm surprised there isn't a Universal binary available for the launcher.

I sort of get the reasoning for not creating a Universal build for Houdini (I still think SideFX should create one, even if it means a larger download size), but it's silly that an app as small as the launcher does not default to a combined build.

I'm not totally sure about which launcher i have installed, but i do see an intel mac production build, but when i click on settings next to the 633 build in the launcher i get this info:

Details for Houdini 19.5.633 - M1
Compiled with clang12.0_11 (macosx_arm64)
Installation Directory: /Applications/Houdini/Houdini19.5.633
Features:
Release Date: Thu Jun 1 2023
HAPI Version: 5.0.7
Size on disk: 3.30 GB

so i guess that's the correct version. I just don't have the feeling everything feels quick and snappy.

It looks good to me, can't help you here i don't have a M1 system.