https://billmccloskey.wordpress.com/201 ... m-project/
"Quantum is roughly divided into four distinct projects.
The Quantum CSS project will replace Gecko’s CSS engine with the one from Servo. Servo’s engine is heavily parallel while Gecko’s is not.
The Quantum DOM project will make Gecko more responsive, especially when there are a lot of background tabs open. When Quantum DOM is finished, JS code for different tabs (and possibly different iframes) will run in separate cooperatively scheduled threads; the code for some background tabs will never run at all.
Quantum Compositor moves Gecko’s compositor into its own process. Since graphics driver instability is a major source of Firefox crashes, we expect that moving code that interacts with the GPU into its own process will make Firefox more stable.
Finally, Quantum Rendering will replace Gecko’s graphics subsystem with the one from Servo, called WebRender. Servo uses the GPU more effectively than Gecko does, driving it more like a game would than a browser."