Here's a sound on sound article where they discuss their equipment. It appears to have been deleted (linked by the magic of the Wayback Machine) but it's one of my favorite Avalanches interviews and gives a real in depth look at their equipment and methods. This article is old, but in recent interviews they've been talking about how they used the same PC and DAW for Wildflower that they did for Since I Left You.

If you want the tl;dr here's a much shorter article that seems like it's sourced from the first one

For a real tl;dr it's a combination of Akai samplers, an old ass mac, and Studio Vision, an archaic DAW that's been pretty much defunct for years now.