Stuff like compression algorithms, some codecs (not all use GPU), some high-performance parsers, some encryption stuff (e.g. openssl), some databases (often col

Stuff like compression algorithms, some codecs (not all use GPU), some high-performance parsers, some encryption stuff (e.g. openssl), some databases (often column stores, also redis I think), language VMs etc use SIMD. More generally SIMD is useful when you are repetitively performing the same instruction on a long stream of data but you don't want to send it over to the GPU because you don't want to incur the many order of magnitude slowdown of sending stuff back and forth to another chip or you can't rely on a GPU being there (e.g. embedded), or it's just overkill.