The speaker discussed vector processing in the context of SIMD (Single Instruction, Multiple Data) instructions on different architectures, particularly ARM and RISC-V. They explained the history and evolution of SIMD instructions, highlighting the different vector lengths and SIMD extensions available on each architecture. They emphasized the importance of predication and how it is used in viable vector length scenarios, allowing for efficient looping and hiding complexity. The speaker also discussed unrolling and alignment considerations in vector processing. They provided specific examples and code snippets for ARM and RISC-V architectures, including details on feature detection and availability of hardware support. They also mentioned the SVP64 project for PowerPC and discussed testing and validation considerations for different vector sizes.