Seeing how the Windows insider app links to a system requirements page, this could mean it wouldn't run as smooth on lower hardware. Thus it will also run slower on a Lumia 920 for example. Or an I thinking wrong? I hope Windows 10 is a faster OS.
Low-end devices will get a different version of the system with less features. So they won't lag.
Also, WP is known to play nice even on low hardware.
Source?
That's not a different version though. But I get what you mean.Life.
JK, the later thing is generally a well known fact.
The first sentance was what I figured out it would be - the same as with Hey Cortana and such.
Low end models won't have the required hardware to run it smooth (or to run it at all), and it won't be on them.