Co-operative and competitive matchmaking will go through Steamworks and allow them extra features like "guest passes" and faster game updates.
"This new back end will allow players to invite friends into matches from their Steam friends lists, and take advantage of the full set of Steam community features including groups, achievements, and Steam overlay chat channels," said developer Relic.
"We are also going to include an all new matchmaking and ranking set up, built specifically for Dawn of War II – Retribution."
"The move to Steamworks will also allow us to provide features like guest passes, free multiplayer weekends, pre-loading and the ability to provide fast turn-around on future patches and updates." Dawn of War II and Chaos Rising are sticking with GfWL.
They won't change to Steamworks "in order to preserve the owners of those titles ability to earn Live achievements as well as their established friends lists", explained Relic. They also revealed no new units will be patched into DOWII or Chaos Rising.
"More details on the beta will be announced at a later date," said the studio. THQ bigwig Danny Bilson says ditching Games for Windows Live was no easy decision. "We've done a lot of research here," said Bilson.
"Microsoft is a fantastic partner of ours. For us to make a decision to go to Steamworks over them required a real deep dive on the part of some of our team."
Dawn of War II: Retribution releases exclusively on PC March 2011.