Rust GPUI vs Electron: 5× Faster Cold Starts and 50% Less Memory

I replaced a familiar tool with a faster one, then watched my laptop cool down.

Your users do not care how clever your stack looks.
They care about a window that opens instantly.
They care about a computer that does not gasp for air. I chased that feeling for months.
I tried flags. I tried tree-shaking. I trimmed icons.
Cold starts still felt like rush hour, and memory graphs looked like a mountain range. Then I rebuilt the same app with Rust GPUI.
The window snapped open.
The fan stayed quiet.
I knew I was not going back. Here is what changed, how it actually felt, and the exact pieces you can copy today.

Why Electron Hurt More Than It Helped Electron is a comfortable trade. One codebase. Easy packaging. A full browser with every feature you might want. The bill arrives at runtime. What ships is a Chromium engine, a V8 runtime, a Node bridge, and your app on top. That stack is generous, but every byte and every thread must wake up before your user sees anything. GPUI flips that bargain. You write native Rust. The toolkit stays small. The OS does more work for you. What the two stacks look like Electron +----------------------+ | Your UI (React/Vue) | +----------+-----------+

          |
          v

+----------------------+ +--------+ | Chromium (Blink+GPU) |<--->| V8 | +----------+-----------+ +--------+

          |
          v

+----------------------+ | Node + IPC Bridge | +----------------------+

Rust GPUI +----------------------+ | Your UI (Rust) | +----------+-----------+

          |
          v

+----------------------+ | GPUI Runtime | +----------+-----------+

          |
          v

+----------------------+ | OS Windows + GPU | +----------------------+ With Electron, I paid a process tax and an allocation tax before the first paint. With GPUI, the first paint felt like a native window because it is one.

The Numbers That Made Me Switch I ran the same minimal project: a window with a sidebar, a list view, and a search box with debounced filtering. Cold start measured as time from process spawn to first interactive paint. Memory measured as RSS 10 seconds after load on the same machine. Benchmark (my dev laptop, repeatable local runs) +------------------+-----------------+----------------+ | Stack | Cold Start (ms) | Memory (MB) | +------------------+-----------------+----------------+ | Electron (React) | 930 | 312 | | Rust GPUI | 180 | 148 | +------------------+-----------------+----------------+ Change: ~5× faster cold starts, ~52% lower memory Your numbers will differ by app size and hardware. The trend is hard to miss.

What Writing the UI Feels Like I expected pain. I received relief. Rust forces me to name data and ownership. GPUI gives me a clear event loop. I stopped sprinkling global state and started thinking in messages and views. The code became boring in the best way. A tiny GPUI example use gpui::{App, Button, Column, Label, State, Window};

1. [derive(Default, Clone)]

struct Cnt { n: i32 } fn main() {

   App::new().run(|app| {
       app.window(Window::new("Counter", ui));
   });

} fn ui(state: &State<Cnt>) -> Column {

   Column::new()
       .push(Label::new(format!("Count: {}", state.n)))
       .push(Button::new("Increment", |s: &mut Cnt| { s.n += 1; }))
       .push(Button::new("Reset", |s: &mut Cnt| { s.n = 0; }))

} No bundler. No hidden process. Build, run, click. The state is a struct. The UI is a pure function from state to widgets. Handlers mutate local state. That is it. The Electron version you already know // main.js const { app, BrowserWindow } = require('electron');

function create() {

 const win = new BrowserWindow({ width: 600, height: 400 });
 win.loadFile('index.html'); // React bundle bootstraps here

} app.whenReady().then(create); The main file is short, but the real work sits behind a browser boot, a JavaScript engine, and a bridge. That overhead shows up on every cold start.

The Architecture Shift That Pays Off My first GPUI attempt felt too clever. I copied a Redux-style pattern and over-abstracted updates. It looked tidy. It slowed me down. I removed the abstraction and returned to a simple message bus. Events ------> [Update State] ------> View(Render)

  ^                                 |
  |------------- Commands ----------|

No magic. A small loop. Clear flow. The app became easier to reason about, and the speed stayed high.

Where GPUI Wins Today

• Launch speed
Fewer processes. Smaller runtime. Native paint. The app feels instant.
• Steady memory
No full browser runtime. Less GC pressure. Predictable RSS.
• Tight feedback loop
Compile times are short. Hot reload options exist. Errors are real errors, not undefined at line 0.
• Battery and thermals
Lower idle CPU. Fans stay quiet during long sessions.

Where Electron Still Makes Sense

• Web dev team, web assets ready
If your team ships React features weekly and shares components with a web app, Electron lowers coordination cost.
• Plugin ecosystems
If you depend on NPM modules that do not have Rust equivalents, porting may cost more than you gain.
• Rapid experiments
When product is still searching for shape, Electron can be a faster sandbox.

The key is honesty about the trade. Performance is not a sprinkle at the end. It is baked into the stack.

A Simple Migration Path Start with one screen that hurts. A settings window or a file viewer is perfect. Build it in GPUI and expose it behind a flag. Measure cold start and memory. If the delta is real, expand. Keep your domain logic in a library crate so both stacks can call it during the transition. Avoid a big-bang rewrite.

What I Would Tell Past Me I held on to Electron for convenience. That felt smart. It was not. The real convenience is an app that starts now and stays light all day. The real win is code that reads like the data it manages. If speed and memory matter to your users, test GPUI on one painful screen. Let the numbers answer the rest.