Re: 64 bit official Windows builds

[Eli Zaretskii]

> Date: Mon, 8 Feb 2016 09:44:53 -0800 (PST)
> From: moocow062@gmail.com
> 
> Could I ask, what is the benefit of 64 bits compared to 32 bits for windows ?

It will run roughly twice faster.

> I can see that if you have to edit files bigger than 2Gb, it is necessary, 
> but otherwise doubling the size of the pointers just makes it slower (halves 
> the cache size) and takes more memory.

First, you can have several large buffers, each one smaller than 2GB,
but all of them together could weigh in at, like, 4GB or more,
something a 32-bit executable, even when running on a 64-bit Windows,
cannot have.

Second, large files happen more frequently nowadays than you may
think.

Third, when Emacs is built with a 64-bit compiler, it runs faster, not
slower, because running a 32-bit executable on a 64-bit Windows
requires expensive thunking for every call to any Windows API,
something that happens a lot.

Btw, Emacs 25 can be built as a 32-bit binary that supports 64-bit
ints, which allows large buffers (up to 2GB), at a price of being
slower by about 30%.