ClickHouse has SIMD implementation for lower/upper for ASCII and UTF-8. It can easily make ~20 GB/sec with 48 cores: https://pastila.nl/?0f15f812/179361234a6b

ClickHouse has SIMD implementation for lower/upper for ASCII and UTF-8. It can easily make ~20 GB/sec with 48 cores: https://pastila.nl/?0f15f812/179361234a6b79d27e18c8db7050bd07 https://pastila.nl/?0f15f812/179361234a6b79d27e18c8db7050bd0... Although it is only using SSE2. And the UTF-8 variant is using a shortcut with SSE2, another shortcut for a subset of code points and a slow path for a generic case.