I read more about the slice-by-N algorithms because they sounded really interesting. The way they work is by using a set of lookup tables that are 4k to 16k in size (larger lookup table for larger N). The reason they are fast is because the lookup tables fit within the L1 cache on modern CPUs. So when you do 100M rounds of CRC32 it is super fast because the table is always cache hot, but I don&#x27;t think this result is informative if you just want to occasionally do a CRC in between doing other types of work (especially for small buffer sizes). You will have to wait as the lookup tables are brought up through the cache heirarchy _and_ you are potentially evicting other useful data from the cache at the same time. Presumably PCLMULQDQ does not have this drawback.