Process-per-site isolation doesn't necessarily have to use (much) more memory.

If you pre-initialize the renderer and JavaScript engine and then fork that pre-warmed instance for each site, every page of memory not written to remains shared in physical memory.

Properly accounting for that in task managers is hard, though; on many OSes, Chrome's memory usage looks much scarier than it is in reality.

You can't fork a GUI process on Apple OSes, most of the system can't handle it.

It'd also weaken any security protection based on randomness (eg ASLR slide, pointer encryption keys).

Huh, TIL Chrome on macOS might actually not be using the “zygote process” paradigm!

https://source.chromium.org/chromium/chromium/src/+/main:con...

Not possible on Windows, where most Chrome users are on.

Because long-inactive tabs should go to sleep.

If Chrome itself is not aggressive enough, try the "Auto Tab Discard" extension.

There is now a Chrome Option "Memory Saver" which dictate how aggressive it is to put Tab into Sleep.

Safari on the other hand doesn't even have Tab Sleep for whatever reason.