Officially, the Intel Core 12 do not support AVX-512, although the cores with P-Core or Golden Cove architecture do support them. The instructions, registers and execution units that make it possible to execute this type of instructions are found in the high-performance cores, which will be used by Intel Xeon with Sapphire Rapids architecture. In the current Intel Core 12, it is as simple as disabling the E-Cores from the BIOS and leaving only the P-Cores to access these instructions from any CPU with Alder Lake-S architecture.
The end of the AVX-512 on Intel Core 12
Well, those of Pat Gelsinger have a very clear idea with the AVX-512, They are for Xeons and not for current desktop CPUs. If we take into account that the P-Cores are the same between the Intel Core 12 and they intend to sell the future Xeon Workstation for HEDT, then it is understood what is the maneuver of Intel. And no, it is not due to a poor support of these instructions, since energy efficiency when making use of them has improved compared to previous generations. What’s more, AVX-512 instructions have been shown to have a higher level of efficiency than AVX2 in tests.
And how do they plan to do it? Technically, they are not going to deactivate them from the processor, but remember that it is necessary to do some work in the BIOS of the Z690 motherboards to be able to activate the use of these instructions. Well, a firmware update for motherboards with Z690 chipset it will remove the ability to activate the AVX-512 from the BIOS. In the same way, motherboards with H670, B660 and H610 chipsets are expected to come with this modification as standard.
However, not all is lost in the face of the AVX-512 in the Intel Core 12, since projects are appearing that seek to inject the old BIOS into the Z690 chipsets, however, it must be remembered that there is always a very high risk when using BIOS without official support. We will see what will be the response of the different motherboard manufacturers and without they will offer support in their chipsets for Alder Lake-S or, failing that, they will succumb to the demands.
Energy efficiency and AVX drives
AVX units are a problem for both Intel and AMD, they are SIMD units that move a large amount of data because they have the ability to perform the same instruction in several blocks of information at the same time. This means that for example Intel limits the maximum clock speed that we can reach with the AVX2 with overclock.
It is documented that the i9-12900K when it has to execute any AVX2 instruction, remember that it is a 256-bit SIMD unit, so it lowers the clock speed to 5.1 GHz due to the fact that it limits the multiplier. Interestingly, the AVX-512 unit that should consume more power is much more efficient in the P-Cores of the Intel Core 12 than the AVX2, which has not undergone internal changes in terms of its implementation compared to previous generations. Let’s not forget that despite the name, the AVX-512 instructions are different from the AVX2 and use a different set of instructions.
