---------------RX 490 will be Announced and Launched on December 12th----------------
AMD are previewing ZEN.. Do you think they will announce RX490 as well? I believe it will be released early next year in the form of Vega.
RX 490 will probably be a dual Polaris - think "Duo Pro" but a pair of RX 480 instead of a pair of FuryX, and downclocked a bit from the RX480 due to heat dissipation limitations.
Announcement I expect on December *13* during their "New Horizons" event.
Vega is probably going to be RX 5xx series.
There have been a few "data" sightings around the web but no solid information on specs, just good solid speculation.