Despite Intel's countless plans to kill AVX-512 on Alder Lake CPUs, older chips can still take advantage of the AVX-512 instruction set under the right conditions. Zingaburga on GitHub recently posted an article detailing how to check which Alder Lake CPU has AVX-512 compatibility for users who want to use the instruction set on Alder Lake.
To check for AVX-512 compatibility, Zingaburga says you'll need to check the batch number on your Alder Lake CPU or the chip you are potentially buying. Batch numbers with V149 or X149 or lower will have the AVX-512 instruction set enabled on the silicon. While codes starting with V150 or X150 through V201 or X201 could potentially support AVX-512, it's not guaranteed.
Codes V202 or X202 or higher will be newer Alder Lake chips with the AVX-512 instruction set fused off, so these chips will not have AVX-512 compatibility of any sort.
But there are still a few other things you need to be aware of to ensure AVX-512 will function. The first is CPU microcode support which needs to be version 0x16 or earlier to enable AVX-512. If you have anything newer, AVX-512 won't work. You can check this by running hardware monitoring apps such as HWInfo64, which will tell you what microcode version your system is running at (HWInfo64 lists it as MCU).
Next is BIOS compatibility, which can range significantly depending on the vendor. According to Zingaburga, MSI is the only reliable vendor that appears to be supporting AVX-512 as a whole. For Z690 motherboards, BIOS version 1.1 or later supports AVX-512, while BIOS version 1.2 includes a CPU microcode toggle to keep AVX-512 support if you need it.
The same appears to be true for MSI's B660 lineup; however, this hasn't been fully confirmed.
With other vendors, it's more of a hit or miss which BIOS's support AVX-512. So you'll have to research the board you are looking at (or already have) to see which supports AVX-512.
Alder Lake's AVX-512 Story
Check out our previous coverage here for a full rundown story of Alder Lake's story with AVX-512. In short, early production units of Alder Lake chips had their AVX-512 instruction sets intact from the factory, but Intel didn't want it enabled for unknown reasons. Motherboard manufacturer's caught wind of this and created a switch to allow AVX-512 right from the BIOS.
Intel countered this with new microcode updates to stop AVX-512 enablement, but even that was countered by the fact that older BIOS microcodes still existed, and users could switch to those versions at any time. Not to mention MSI's brilliant strategy of building a microcode switcher into newer BIOS's made the process easier for users.
Finally, Intel put an end to all of this by permanently fusing off the AVX-512 module in newer production models of all Alder Lake processors.