I have to admit that I'm not super impressed with the results here. Based on the talk that pcwalton did: https://www.youtube.com/watch?v=erfnCaeLxSI I was expected it not to just be a little faster than Chrome, but to, like, double the speed, or more.
Is it that these are just not good candidates for showing how much faster than webrender can be? Or has Firefox slowed it down vs. in Servo maybe?
WR's architecture has changed significantly from that talk, for the better. In particular aggressive use of early Z has made our fragment shading performance go way up since then.
In Nightly you can turn WR on via about:config. But be warned that there are quite a few problems, including performance problems, that still remain. The foundation is solid, but the CSS rendering model is complex, and there's a good amount of engineering work that just has to happen to make every corner case fast. (For instance, parts of Ars Technica were recently found to be slow because the particular interaction between the CSS features it was using was causing Gecko to generate a ton of clipping operations for WR... there's no substitute for engineering polishing work that has to happen in cases like that.)
I use it in nightly via the config flag; it is pretty great but there are still some glitches from time to time.
Last I was looking at this, the big WebRender flag wasn't expected to be faster due to the specific way it was integrated, you need the more aggressive setting to get pure WebRender.
https://mozillagfx.wordpress.com/2017/09/25/webrender-newsle...