I wont try to go into details of what a CPU is or how they work, anything I write is going to be worse than other readily available explanations online. Actually, I wont really explain how any computer component works, this is about the nintendo64 and its peculiarities so I will try to focus on whats special about its CPU or else I will never finish this

So... I tried to think of a better way to talk about this, but I can't find another way to describe the n64 emulation other than utter chaos. And I'm not alone, there are quite a few people confused and/or complaining online. (add mais links?)

If you have previous experience with emulating other consoles you may be surprised at the fragmentation of efforts and the unreliability of n64 emulation.

UltraHLE:

First successful N64 emulator, merely 3 years after the N64 release.

Smart use of High Level Emulation, i.e. instead of simulating absolutely everything the RCP did down to its transistors (Low Level Emulation) it does some smart mapping of system calls (i feel this is similar to steam's proton but i may be very wrong) to approximate the expected result and thus cut down on the complexity and processing. Aside from being the "first" emulator, it is irrelevant nowadays since it was discontinued a long time a go.

Project64:

Even though it had a closed source period, this emulator was once considered the best of its time and its legacy can still be felt in other emulators to this day (for better or worse).  It defined the first plugin spec, known as Zilmar Spec, that would become the general approach to N64 emulation.

There are lot of criticism online directed to the project lead for some of his decisions and the direction in which the project has been going (such as old bundled plugins and per-game timing fixes instead of focusing on cycle accuracy).

You can still get a pretty good experience depending on the game you want to play and by messing around with parameters, plugins and etc.

Also, if you ignore some insane problems it had in the past, a pretty serious vulnerability has been found on it so it isn't the safest option if you are downloading random ROMs from the internet.

Windows support (and only windows).  

Plugins:

This is kinda hard to place on a timeline since it is essentially a second timeline happening in parallel with the history of emulators but I think this is where it makes more sense narativelly.
 

So, whats all this plugin deal about? Well, this approach started with proejct64 and it kinda stuck ever since.

The idea is simple, an N64 is made of different parts so lets emulate those as diferent things and plug them together to make an emulator. For this to be possible, the plugins need to be consistent, follow some kind of specification.

The first specification was made by Zilmar, the steward of project64 and was the dominant spec for a good while. However, this spec is ANCIENT and since they were feeling constrained by it the Mupen team created their own spec (insert xkcd joke about specs), breaking compatibility with project 64.

RDP Plugins:

ParaLLEl-RDP - LLE video plugin, runs on the GPU through the use of the Vulkan shaders "This is currently considered the best video plugin by most measures". Supports hi-res upscalling but due to being an LLE emulator it lacks support for widescreen hacks or high-res textures (but GLideN64 has those!). High system requirements and needs a GPU with Vulkan support. Needs to be used with an LLE RSP plugin.

GLideN64 - A hybrid HLE/LLE plugin, not to be confused with Glide64 plugin by the same author (keeping track of the genealogy of these things makes me want to murder someone). "This is the best HLE plugin by far." Supports: mip-mapping, emulation of low-level triangles, microcode emulation of every game, gamma correction, flat and prim shading, VI emulation,  LLE graphics, hi-res custom texture support, MSAA and AF, a widescreen hack, and even some shaders. It is the only plugin that has implemented HLE support of microcodes for every N64 game.

Use this over ParaLLEl-RDP only if you are unable to run the latter in HD at full speed or if further enhancements such as widescreen hacks and hi-res textures are desired.

RSP Plugins:

Not as contentious as the RDP plugins, if you are using ParaLLEl-RDP (which you probably should) your best bet is to stick to ParaLLEl-RSP.

Input Plugins:

NRage Input - the best plugin.

Audio Plugins:

I'm confused, send help

Faltando em algum lugar:

-libretro coisas

-audio coisas

-rsp pra hle

- seja la q porra o ares ta fazendo com MAME coisas

- simple 64 e outros dropando plugins

- push recente pra compatibilidade e acuracia real, removendo per game hacks

- 2020 Nintendo data leak (GigaLeak)