[WestCoastJustin]

You are right. Sorry for the confusion. It is only PD (Persistent Disk) that comes out of network bandwidth. Anything on the NVMe SSD would be totally local to the machine (no network caps, etc). The article doesn't really say if they are using SSD PD or SSD NVMe for GCP. Also, disk size does matter for the NVMe SSD and performance (as you can stripe them together by adding more; up to 4). You can see the #'s by using the console and playing around with adding more NVMe SSDs (via this doc [1]).

  Size      Random IOPS                Throughput limit (MB/s)
  375GB     169,987 (r)  90,000 (w)      663 (r)   352 (w)
  750GB     339,975 (r) 180,000 (w)    1,327 (r)   705 (w)
  1125GB    509,962 (r) 270,000 (w)    1,991 (r) 1,057 (w)
  1500GB    679,950 (r) 360,000 (w)    2,650 (r) 1,400 (w)

[1] https://cloud.google.com/compute/docs/disks/local-ssd