Comment by dathinab

you seem to have a misunderstanding about how quantum computing works

it isn't "faster" computing

it is "different" computing

like if you make a diagram left side "things computers can do fast", right side "thinks they can't do fast", then quantum computers are like a oval in the middle covering part of both sides

as consequence weather it "outperforms" HPC (in general) is fully meaningless, it likely won't ever do that, but also still will break cryptography anyway

and in general it's commonly used in conjunction with HPC, not as a replacement of it

quantum computers working "different" instead of "faster" is also why we won't see a slow breaking/reducing of cracking time for asymmetric crypto. Because it isn't a slow buildup of speed. It's a overcoming of technical barriers. Once done breaking RSA/ECC on a 128 bit security level will pretty much instantly jump from "infeasible per key" to "in minutes per key".

this is also why even "just" a chance of idk. arbitrary chosen 30% that it will be possible in 2030 would be too much to ignore it... especially if we consider that most computer security out there is coupled to asym. crypto not breaking in one way or another.