None of the problems he cites are issues with his code, though, nor are they as much of an issue with modern processors. Unless I'm missing something, the pres

None of the problems he cites are issues with his code, though, nor are they as much of an issue with modern processors. Unless I'm missing something, the presentation he cites are running on the Cell processor, not a modern x86 system. RAM cache misses are pretty bad, but with the blocks that he's dealing with, he's looking at maybe 1 miss per block, and that's assuming that the processor is letting the blocks get entirely out of the 3 levels of cache to RAM. The compliment array should stay in memory 100% of the time because it's tiny and referenced constantly, and the individual arrays shouldn't be that bad. He's not branching all that much, so unless the while and for loops are triggering after 1 or 2 characters, it's unlikely that's the issue. The actual problem he's more likely running into is the OS rescheduling the thread to a different core, which is a gigantic hit.