Hope this helps clear some things...
My experience with ALL ATI cards is that "theater mode" is selectively included and excluded at the discretion of the driver release... it is unreliable to depend on cuz sometimes the driver includes the option, sometimes it doesn't..
case in point:
I have updated my laptop ATI drivers to newer drivers and then had to drop back to legacy drivers cuz new releases pulled out theater mode which I feel is ESSENTIAL for the most dependable Resolume experience.
I go to computer stores and check all computers that run ATI video cards. I check to see which ones have theater mode and there is no rhyme or reason, in some drivers it is there and some it is not.
Matrox cards call their version of the technology: "dvdMAX"
on my desktop pc (what I perform on) I use the Matrox Pharelia. Matrox has kept "dvdMAX" as a standard feature in EVERY driver release for at least 4 years. I wish ATI had the same level of reliability.
in desktops you have the option of choosing which video card you want... in laptops you are stuck.
So be advised all ATI cards CAN "technically" run theater mode... but depending on the driver release you MAY or may not be able to utilize this feature.