The OG Steam Deck (7nm, comparable to the Series S) has a die size of ~162mm2. In there, it packs an 4 core, 8 threads CPU and a 8 CU GPU.
On the other hand, the Xbox Series S packs an 8 core 16 threads CPU with 20CU GPU of the same architecture in ~197mm2 die.
This is a technical question, how come the Series S packs much more in just 25% more size? I’m not saying the Steam Deck should be as powerful as a Series S (that’d never happen, the power constraints would not make it possible), but I wonder if the CPU in the Series S is cut-back or if there’s anything in the Steam Deck’s SoC that could have been removed to get a lower cost.
4 more cores would take about 20 mm^(2) and 12 more CUs would take 28 mm^(2). So that would reach 210 mm^(2) (ignoring ROPs and the like, which might take some more space). However, space is cut in some other places. For example the Series S doesn’t have AV1 decoding while the Steam Deck does have it. Also, as mentioned, memory controllers will have a different size.