After 23 years, AMD's ancient 3DNow! instructions are finally being retired from the Linux kernel (via Phoronix). Starting with Linux version 5.17, older AMD processors with 3DNow! support will no longer run those instructions within Linux operating systems featuring the updated kernel.
AMD released the 3DNow! instructions in 1998 to improve CPU functionality by adding SMID instructions to the base x86 instruction set, thus enabling vector processing of floating-point operations using vector registers. The first implementation had over 21 new instructions that supported SIMD floating-point operations.
In the late 90s and early 2000s, these instructions were popular for improving gaming, video playback, and even Photoshop workflows. AMD supported the instructions with CPUs spanning from the K6-2 to K10 chips.
However, Intel introduced its competing SSE instructions shortly after AMD released its 3DNow! instructions for the K6 CPU. The SSE instructions became dominant with the arrival of Pentium 3, so AMD also adopted SSE by the time SSE2 arrived on the scene.
AMD continued to adopt Intel's SSE instruction sets, so 3DNow! finally died when the first FX CPUs launched. The Phenom II chips were the final CPUs to support the instructions. Now SSE and its multitude of variations, including SSE2, SSE3, SSE4, 4,1,4A, SSE5, and more, are the standard.
After 23 years, 3DNow! is finally going away on the Linux platform forever through the removal of 500 lines of code that have lived in the kernel for more than two decades. In the unlikely event that you have any old programs that require AMD's home-brewed instruction sets, Linux 5.16 is your last stop on the upgrade train.