Considering how big GPU silicon is, when you have both integrated and custom, it'd have made sense to integrate them.
We don't know price yet, but if it's like the deck they'll be trying to keep it as cheap as possible. The deck supposedly was so off-the-shelf that it re-used a design for another AMD customer, leftover elements and all - https://boilingsteam.com/an-in-depth-look-at-the-steam-deck-...
Unless Valve took a big risky bet, the Steam deck is going to be again re-using existing hardware and excess hardware. I'm presuming there are leftover unsold Zen 4 and RDNA 3 dies - and nothing competitive that AMD could offer from Valves perspective, at least when they locked the design some months ago.
I hope that if this is a success, they'll have the numbers to justify a Strix-Halo like APU with a smaller CPU but keeping the big GPU for the next generation of the device.
Why? Desktop PCs, especially gaming PCs, have nothing to gain and everything to lose by oversubscribing system memory with GPU workloads. The memory bus typically isn't fast enough anyways, and a modern PCIe x16 can easily handle the bandwidth of a gigantic GPU. The only advantage to unifying everything is latency, which isn't relevant at any framerate under 1000hz.
> when you have both integrated and custom, it'd have made sense to integrate them.
Sometimes, sometimes not. AMD's mobile packaging technology is not world-class like Apple and Nvidia's is. Valve had the experience with the Steam Deck to make the call if a mobile architecture was the right choice, and they decided against it.
Valve doesn't have to make a Mac. This is a gaming device, it's designed accordingly.
How are SOCs going to replace full-fat ATX cards when they can't even beat the thermally-throttled version? The SOC isn't even more energy-efficient, here.