Kagamin wrote:
> The Duff's device is said to be an optimization, but I get blunt device only 0.7% slower.

Read Duff’s post: “this loop was the bottleneck in a real-time animation playback program”, and all the Device is doing is unwinding the loop a few times.  Optimization comes because — on the particular system the code was written for — the eight-times-unwound loop fit nicely into cache.

—Joel Salomon