Apparently all the "brain" is located on the top half. The boards are significantly more dense.

Next up we remove the "CD board".

Why the CD board?

I don't know. It will be a good question to think about while we pop the connectors and remove the screws.

Or wonder about what the ICs behind the heatsink/label actually do.

I bet the one behind the label is a storage unit, like ones in a flash drive.