Wednesday, February 2nd 2022
MSI Partially Reenables AVX-512 Support for Alder Lake-S Processors
Intel's Alder Lake processors have two types of cores present, with two distinct sets of features and capabilities enabled. For example, smaller E-cores don't support the execution of AVX-512 instructions, while the bigger P-cores have support for AVX-512 instructions. So Intel has decided to remove support for it altogether not to create software errors and run into issues with executing AVX-512 code on Alder Lake processors. This happened just months before the launch of Alder Lake, making us see some initial motherboard BIOSes come with AVX-512 enabled from the box. Later on, all motherboard makers pulled the plug on it, and it is a rare sight to see support for it.
However, it seems like MSI is unhappy with the lack of AVX-512, and the company is reenabling partial support for it. According to Xaver Amberger, editor at Igor's Lab, MSI reintroduces selecting microcode version with its MEG Z690 Unify-X motherboard. There is an option for AVX-512 enablement in the menu, and it is indeed a functional one. With BIOS A22, MSI enabled AVX-512 instruction execution, and there are benchmarks to prove it works. This shows an advantage of 512-bit wide execution units of AVX-512 over something like AVX2, which offers only 256-bit wide execution units. In applications such as Y-Cruncher, AVX-512 enabled the CPU to reach higher performance targets while consuming less power.
Sources:
Xaver Amberger (Twitter), Igor's Lab
However, it seems like MSI is unhappy with the lack of AVX-512, and the company is reenabling partial support for it. According to Xaver Amberger, editor at Igor's Lab, MSI reintroduces selecting microcode version with its MEG Z690 Unify-X motherboard. There is an option for AVX-512 enablement in the menu, and it is indeed a functional one. With BIOS A22, MSI enabled AVX-512 instruction execution, and there are benchmarks to prove it works. This shows an advantage of 512-bit wide execution units of AVX-512 over something like AVX2, which offers only 256-bit wide execution units. In applications such as Y-Cruncher, AVX-512 enabled the CPU to reach higher performance targets while consuming less power.
10 Comments on MSI Partially Reenables AVX-512 Support for Alder Lake-S Processors
What can I say, it's not really helpful on the desktop, but in the odd case you need AVX512, if Intel already wasted the die area on it, why not have the option avaialble?
It's been on intel server chips for the last 5 years but hasnt seen widespread acceptance, in part due to feature support being a mess compared to AVX/AVX2.
It would be nice to see more widespread use, when sins of a solar empire rebellion received AVX support in 2019 it made a huge difference in performance in late game.
Seems to me intel would have been better off making a 10 P core i9, but then they couldnt brag about having more threads then AMD or something like that.
The issue is when you have E-cores enabled, and what happens when a program tries to execute an incompatible instruction on the E-core. I know some have claimed they tried to implement a mechanism to stall the thread and move it to a P-core. If this is true, then the mechanism probably didn't work reliably. I can't believe they didn't realize having different ISA support on cores would result in problems requiring a hardware solution. Either way, it's an embarrassing screw-up from their side.
The proper solution would be to implement AVX-512 on the E-cores too. And contrary to what people would believe, it doesn't have to be very costly. Because the purpose of this implementation would be to prevent stability issues, so it wouldn't have to be a fast implementation. They basically could split up most operations, and just a few would need extra logic.