I've heard this claim too: apparently Facebook tested a lot of routers, and they consistently routed v6 ~500us faster than v4. v6 has no checksum, so routers do

I've heard this claim too: apparently Facebook tested a lot of routers, and they consistently routed v6 ~500us faster than v4. v6 has no checksum, so routers don't need to recalculate it when they decrement the TTL header, and it does make sense that removing a step would help. Unfortunately my source for this is "I heard it from someone that works at Facebook". In practice this is only a small part of final performance, so you need to do end-to-end measurements to get a proper idea of what people will experience. Both Facebook[1] and Apple[2] have done that, showing 10% faster page loads and 40% faster connection establishment respectively on v6. Even if that was solely down to routing policies, it's still a measurable difference. [1] https://engineering.fb.com/2015/09/14/networking-traffic/ipv6-it-s-time-to-get-on-board/ https://engineering.fb.com/2015/09/14/networking-traffic/ipv... [2] https://www.sidn.nl/en/news-and-blogs/apple-connections-established-40-per-cent-faster-with-ipv6-than-with-ipv4 https://www.sidn.nl/en/news-and-blogs/apple-connections-esta...