Modern supercomputers essentially <i>are</i> large commodity clusters.  Nobody builds a single fast machine ala Cray-1 anymore.  It&#x27;s just not scaleable past a certain point and we&#x27;re long since past that.  However, they still like to give them fancy names as marketing, because they cost tens of millions of dollars.<p>The main differentiation vs a standard datacenter is low-latency high-throughput interconnects, often with a specific or reconfigurable topology.  Something like InfiniBand, where you can ensure very consistent, very favorable bounds on your latency and throughput.  So think of it as being a &quot;custom installation&quot; or &quot;custom cluster&quot; instead.<p>Nowadays there really are only a few real choices left in high-performance computing hardware: CPU vs GPU, processor architecture (eg POWER vs x86), and interconnection.  Everything else is more or less irrelevant.<p>I have to admit though, I&#x27;ve always wanted to see what you&#x27;d get if you built a Cray-2 with GPU chips (eg Pascal) or Xeon Phi as processing modules.  The sheer density of chips Cray managed to cram in that case is impressive.