Although not officially DRM-oriented, the same question applies to TCPA and Palladium (renamed "NGSCB" since). From what I understand TCPA is oriented towards safe key storage and TCPA compliance certification, while Palladium adds a program identification and authentication dimension.
Here is a technical analysis of TCPA and Palladium. The part on TCPA is accurate, from what I read from the TCPA specs, but the part on Palladium has a very strong bias and a very poor technical foundation (it is possible that less details were public at the time though).
A correct description can be found in Manferdelli's presentation.
Palladium basically creates new hardware-enforced "safe" (or "trusted") zones in the memory, a trusted user-mode memory and a trusted kernel-mode memory, and also a new CPU mode that can access these memory blocks.
The access to trusted memory is controlled. Only the "nub" or Nexus, a very simple kernel-like program, has access to the trusted kernel-mode memory.
The parts of the programs that run in the trusted user-mode memory are isolated from each other. User programs that need access to secure functionalities (program authentication, blob encryption, key storage) have to interact with the nub to do so. These potentially trusted user pieces of code (running in trusted memory) are called agents (Notarized Computing Agents or NCAs) and they can be identified and authenticated locally and remotely.
This could be the end of cheating in online multiplayer games, for example, as the executable would have to be verified and an attestation provided to the hosting servers before a game could be started.
This could also be used to limit what software agents are used to view some piece of media.
Links
http://www.eros-os.org/pipermail/cap-talk/2003-March/001117.html
Here are some details
EFF on Trusted Computing
http://yro.slashdot.org/article.pl?sid=03/10/02/2230200&mode=thread&tid=123&tid=126&tid=172&tid=99
Difference between TCPA and Palladium: secure display and input
http://linux.slashdot.org/article.pl?sid=05/02/02/1543255
Clarifying misinformation about TCPA
http://www.research.ibm.com/gsal/tcpa/tcpa_rebuttal.pdf
Palladium/NGSCB and TCPA are not the same thing. There is no remote attestation in TCPA and no TOR (secure os/memory).
(via http://linux.slashdot.org/article.pl?sid=05/02/02/1543255 )
Why we need TCPA
http://www.research.ibm.com/gsal/tcpa/why_tcpa.pdf