No it is not true. That box is more for NLE's. That's why it refers mostly to the Mercury Playback Engine (Premiere Pro). The help it gives you with After Effects, as mentioned in this PDF on their site [link], is that it gives you "What You See Is What You Get". Basically, it outputs your AE comp to an external screen (ideally a broadcast monitor) so you can see what the color will actually look like. (A regular computer monitor doesn't show proper color.)
Nowhere on the site does it say anything about speeding up your work in AE. All the speed increase (if any) would be in Premiere or when encoding a final compressed file in H.264.
- The Great Szalam
(The 'Great' stands for 'Not So Great, in fact, Extremely Humble')
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