Most sites are fast on a modern engine, but online banking, government portals and corporate intranet systems often only work with the old one. The dual engine uses the fast core by default, falls back to the compatibility core when a page fails or renders badly, remembers the choice, and uses the right engine next time.
What each engine does
The fast engine renders modern pages with quicker script execution and smoother animation; the compatibility engine handles legacy sites, ActiveX controls and internal systems built on old standards. Both share one set of bookmarks, passwords and settings, so switching never loses your state.
- Fast engine: everyday sites, video, online documents
- Compatibility engine: banking, government portals, intranet systems
- Shared bookmarks and passwords, no loss of login state on switch
- The address bar shows the current engine and lets you switch by hand
When it switches automatically
The browser decides based on site characteristics, visit history and a built-in list. When a page comes up blank, a control fails to load or a certificate warning appears, it reloads once with the compatibility engine.
- Automatic retry when a page fails or a control is missing
- Remembers the engine choice per site after the first switch
- Built-in list of common finance and government sites
- Pin a fixed engine for a specific site in settings
How to control it manually
If you would rather a site always open in a given engine, click the engine icon on the right of the address bar, switch, and tick "remember my choice" — the site keeps that engine from then on.
- Switch instantly from the engine icon in the address bar
- Per-site engine preference is remembered
- Engine rules can be exported for bulk deployment
- Enterprise edition can push engine policies centrally
FAQ
Does a dual engine make the browser slower?
No. Engines load on demand, only one runs at a time, and the unused one costs no extra memory.
Why does a site look different after switching?
The compatibility engine parses older layouts differently. That is expected — it is what makes controls and forms work.