Comment by fitshipit

I believe based on context that you and the article are talking about different kinds of parallelism. Yours is the more usual sense, the author seems to be referring to the fact that CRC does not exhibit instruction level parallelism which out-of-order execution exploits. This is because the loop is very tight (probably a few instructions) and each iteration depends on the results of the previous, so there is only a tiny window for reordering instructions.