The Steam edition will use only Steam for DRM. However, as EA did not start selling Dragon Age 2 through Steam until after it had stopped offering a free upgrade to the bonus-packed 'BioWare Signature Edition,' even Steam aficionados might have gone for a retail copy.
DRM on the retail edition is a different affair, with a combination of two different systems. 'Release Control' will be used to ensure that should you receive a copy before the game officially launches in your territory, you won't be allowed to play it until the powers that be say so. Release Control will remove itself once the game has launched.
The other, more persistent layer of DRM on retail copies has no disc check and does not limit the number of PCs you can install the game on. After verifying ownership by logging into your EA account when installing, you'll be able to play the game on five different PCs within any given 24-hour period. While you can play offline, it'll periodically require you be online for a login check, at yet-undecided intervals.
Dragon Age 2 launches for PC, Xbox 360 and PlayStation 3 on March 8.