Depends! HPC is a massive umbrella term. Which part of it are you interested in? For finance, firewall-to-firewall time was an important concept. (The time it

Depends! HPC is a massive umbrella term. Which part of it are you interested in? For finance, firewall-to-firewall time was an important concept. (The time it takes a signal to get into your datacenter, be processed, then emit a signal back out.) But e.g. massive data processing is an entirely different beast. Latency isn't too important, whereas parallelization is crucial. So it's kind of hard to make a list without being pointed in a vague direction.