This reminds me of an article I read a while back: https://hackernoon.com/server-side-rendering-shootout-with-m...

Not sure if the benchmarks still hold now that React 16 is out, but there's definitely overhead in the general approach.

> HTTP can only send strings/bytes, so it makes sense to start there and skip the overhead of building up a virtual DOM representation first. There’s a reason string based templating languages are so much faster than our modern frameworks using a virtual DOM implementation.

Hm, I'd guess, it's latency to backend servers. Cores are plenty fast for just about every language.

If you have a good network between systems, each request of any form to a backend service will introduce at least 0.5 ms of response time due to datacenter RTA, so once you hit 250 queries, that's that. And 250 queries are just one n+1 problem somewhere.

The OP says the call is CPU bounded, which suggests that even if time is spent on the network, it is a minority of the total time.