$Amazon(AMZN.US) In an industry racing to scale up, AWS has remained restrained. On scale-out clustering (linking multi-chip clusters), it has largely stood pat.

- Bandwidth held flat across two generations. AWS’s EFA cluster network delivered 200 Gb/s per NIC in both. Over the same period, Nvidia went from 800G to 1.6T (8x AWS), while Google moved from 100G to 400G (2x AWS).

- Smaller domains than Google, yet lower bandwidth. The smaller the scale-up domain (a set of directly connected chips), the more traffic is forced onto scale-out. Google runs nearly 10k cards per domain and still raised bandwidth 4x; AWS domains have just 144 cards and only 200G, below Google.

- Key switch silicon is sourced externally. NICs (Nitro) and white-box switches are built in-house, while the switching chips are procured from Broadcom and Marvell.