If you hunt around you'll find that chrome is even doing things like speculative DNS queries, opening TCP channels to endpoints that are often opened on pages that you might be trying to load, in some very limited cases even pre-downloading and executing a page "hidden" only to swap it in like you changed tabs once you "hit enter". [0][1]

If you tend to be pretty "habitual" when using chrome, fire up something like wireshark before opening it and watch what it does when you first start it. A year or 2 ago I did this and noticed it would instantly fire off DNS queries for gmail and start a TCP channel before i've even typed anything! (as at the time the first thing i'd do when opening chrome was check my email).

It's really cool shit, and I'm sure chrome and safari aren't the only ones doing it. I mean the gains can be substantial (especially for mobile devices! getting the DNS query and TCP handshake out of the way on a shitty 3g network before the user stops typing means it will load a few hundred ms sooner) and for many of the smaller changes there are very few downsides.

[0] This goes over the bit ones that many browsers have: https://css-tricks.com/prefetching-preloading-prebrowsing/

[1] Here is a somewhat-technical article about chrome from 2012 that goes over the DNS and TCP-preconnect stuff: https://www.igvita.com/2012/06/04/chrome-networking-dns-pref...