This feature promises 400% increase in responsiveness and a 700% improvement while loading web pages.
We told you all the details published Mozilla about it.
A few months ago, Mozilla launched multi-process Firefox to some users.

As we clarify, this new feature is gradually coming to all users who did not have extensions installed.
Undoubtedly, it is a novelty that is worth trying and has available.
Firefox multiprocessing continued to reach users with version 49, even if they had installed extensions.

However, these had to meet a series of iron parameters.
Yes, they should not need to be marked as incompatible with this function by its developers.
That could happen with the release of Firefox 51 if everything goes as planned.

In particular, two new features will be addressed by the technology that we will discuss below.
The first is to get more performance with multithreaded architecture, minimizing the impact when errors occur.
In the second place, they will address the implementation of a sandboxing to improve the safety of multithreaded.