I think the gpu and CPU clocking Thing will work like this, i have it on a good hunch:
Devs will prioritise modes like high clocked GPU and lower clockd CPU, or the other way around. That is basically what the presentation says, they will have trouble hitting full speeds on both parts simultaneously due to utilisation (which is a bit duh), so one Part being higherclocked requires an under utilisation of the other. So a game that is mostly gpu limited will use a gpu Mode, a very intense open world game or... Some other Design requiring more CPU will use a CPU Mode. So underclocking the GPU there.
This of course assume that games do not really heavily utilise both parts at the same time, in which case, like a 60 Assassin's Creed game as we see on PC. Or a game with variable drs and a lot of CPU Stuff. Or any ambtious game that want to do both simulation and graphical things.
The one Part being higher clocked, requires an under utilisation of the other. Hence why freefloating resolution game with very preise dynamic resolution scaling, like Doom, Titan Fall 2, modern warfare etc. Will all probably need to be in the Mode for GPU Power. They are already maxing the GPU as is due to their Design.