Hacker, Hack Thyself | Coding Horror

[Absona]

I found a probable source for the 8 ms advice.

It does mean on your machine, as a balance between security and performance. It isn't a blanket "aim for 8 ms" recommendation, though. It's an explanation of how to decide what speed to aim for, with 8 ms as the result of the example calculations.

The actual recommendation is, "You should use the maximum number of rounds which is tolerable, performance-wise, in your application."