Not entirely. With Skylake, there was a clock speed penalty for "heavy" 256b instructions and "light" 512b instructions, and a steep clock speed penalty for "h

Not entirely. With Skylake, there was a clock speed penalty for "heavy" 256b instructions and "light" 512b instructions, and a steep clock speed penalty for "heavy" 512b instructions. With Ice Lake, there is a very small single-core clock speed penalty for 512b instructions. There is no clock speed penalty after Ice Lake. (Which, for non-server CPUs, is currently a list containing one generation: Rocket Lake.)