FOUND: Intel s downfall mitigations drop performance up to 39 tests show - What They Never Told You

Intel recently disclosed Downfall, a security vulnerability that affects multiple generations of Intel processors - some of which used to be the best CPUs on the market. The chipmaker has rolled out an updated software-level microcode with a fix for the flaw. However, it has caused some alarms since there's a potential claimed performance impact of up to 50% on AVX2 and AVX-512 workloads involving the Gather instruction.

As a quick recap, Downfall (CVE-2022-40982) is associated with the memory optimization feature inside Intel processors. Downfall exploits the Gather instruction, which speeds up the processor where Intel chips fetch data scattered in different places in the memory. The Gather instruction inadvertently exposes internal hardware registers to software, allowing the latter to tap into data kept by other software. Downfall affects Intel mainstream and server processors, spanning from the Skylake to the Rocket Lake microarchitecture. Therefore, you're likely affected unless you own one of Intel's more recent processors, such as Alder Lake, Raptor Lake, or Sapphire Rapids. Intel has put up an extensive list of all the affected chips.