I run dual xeon gold 6130 in my server and those have avx-512. I was wondering if Siril supported it, or if it stops at avx-2.
Hello and welcome.
In general, specific hardware features are not available in generic software releases, if you build it on your machine it will probably be available, but I don’t know to what extent it will be used. A benchmark between the official release and your optimized local build would be nice to see 
I run dual 6136 and for Rawtherapee, skylake builds are faster than skylake avx-512 builds. I suppose it’s due to throttling.
How siril performs may be different though.
avx-512 has a way higher power use on Intel CPUs and that’s why they clock lower. you are probably better off to stick to lower level AVX versions.
I already have them and can’t switch lol. that’s why i’m wondering if it uses AVX-512. i can’t find anything about it online
your xeons also support avx 128 and so on. you will be fine.