I worked with a Cray back in 2012 and the amount of engineering that goes into each rack and down to each blade is incredible. The biggest thing that got me was

I worked with a Cray back in 2012 and the amount of engineering that goes into each rack and down to each blade is incredible. The biggest thing that got me was the geometry of the heatsinks that were designed to slightly compress air as it left each blade into the one above it.