Note that they're running R630/R730s for storage. Those are 12-year old servers, and yet they say each one can do 20 Gbps (2.5 GBps) of random reads. In comparison, the same generation of hardware at AWS ({c,m,r}4) instance maxes out at 50% of that for EBS throughput on m4, and 70% on r4 - and that assumes carefully tuned block sizes.
Old hardware is _plenty_ powerful for a lot of tasks today.