Optimized repositories: Added caution about Intel +12th gen AVX-512

support and why its now disabled.

Author: Shendisx

src/content/docs/features/optimized_repos.mdx

@@ -41,6 +41,18 @@ If you’re currently using the x86-64-v3 repositories and your new CPU supports
 
 ### Checking CPU Compatibility
 
+:::caution
+Intel 12th gen (Alder Lake) and newer CPUs may report `x86-64-v4` support, but in practice they **cannot run AVX-512 instructions**.
+
+Why?
+- **Hybrid architecture conflict**: The big “P-cores” support AVX-512, but the small “E-cores” do not. Running AVX-512 while E-cores are active would cause instability.
+- **Intel’s workaround**: To avoid this mismatch, Intel disabled AVX-512 in two ways:
+  - **Microcode/BIOS updates** (early Alder Lake chips): AVX-512 could be re-enabled by avoiding or rolling back microcode updates.
+  - **Hardware fusing** (later 2022+ chips): AVX-512 is permanently disabled at the factory, making it impossible to re-enable.
+
+Because `x86-64-v4` requires AVX-512, these CPUs should be treated as **x86-64-v3 only**.
+:::
+
 - Verifying `x86-64-v4` support:
   ```sh title='Run the following command:'
   /lib/ld-linux-x86-64.so.2 --help | grep supported