[lisper]

This was my thought. Nanoseconds are an eternity. You want to be using Planck units for your worst-case analysis.

[itishappy]

Planck units are a mathematical convenience, not a physical limit. For instance, the Planck mass is on the order of an eyelash or grain of sand.

[lisper]

Planck units are physical limits. The Planck mass is the limit of the mass of an elementary particle before it would form a black hole.

[u1hcw9nx]

If you go far beyond nanoseconds, energy becomes a limiting factor. You can only achieve ultra-fast processing if you dedicate vast amounts of matter to heat dissipation and energy generation. Think on a galactic scale: you cannot have even have molecular reaction speeds occurring at femtosecond or attosecond speeds constantly and everywhere without overheating everything.

[lisper]

Maybe. It's not clear whether these are fundamental limits or merely technological ones. Reversible (i.e. infinitely efficient) computing is theoretically possible.

[UltraSane]

If you have a black hole as an infinite heat sink this helps a great deal.