I've noticed couple of potential improvements that we could make to make rendering faster. I didn't implement them yet, because it won't make much of a difference. Currently the slowest thing on the server is actually Steem API. It can even take more than a second to fetch data (for example post contents). Rendering our app doesn't take that much compared to that.

We plan to migrate to our own API, so we can fetch data in exact format we need. In addition it should be way faster than Steem API, so after we migrate to our own solution we can work on improving the performance even more.

The most obvious one I notice (and it is worth considering no matter if you are running React server-side or client-side) is to process and render data only on-demand. Take sorting votes as an example. In feed you have 20 posts, sometimes they have more than 10 thousands of votes. Does it make sense to sort them right now, even though user might not even consider taking a look at them? I don't think so. It makes sense to do this when we know this is necessary - when user opens votes list. We can show loading icon for a while and present user a final result.

This is very simple change, but can make a difference. You might have slow-running tasks, but if you don't run them (unnecessarily) every time user visits a website it's not big deal.