Since for at least 2010 we’ve had laptops with integrated GPUs inside the chipset. These GPUs have historically been very lacking (I’d say, extremely so, to the point that a Tiger Lake 11400H CPU, which is quite powerful, wouldn’t reach 60fps on CSGO a 1080p with the iGPU. AMD SoCs fared better in that aspect, but are still very lacking, even in their most recent RDNA3-based iterations, due to the poor bandwidth these laptops usually ship with (at best, dual channel DDR5 ram, but mostly dual channel DDR4). As such, dedicated GPUs with their own GDDR6 RAM and big dies have been necessary for both laptops and desktops whenever performance is a requirement, and lowend dedicated GPUs have been considered for those manufacturers that want slim, performant laptops with a decent battery life.
At the same time, there have been 3 important milestones for the APU market:
- In 2007 the Xbox 360 shifted from a Dedicated GPU + CPU combo for a single GPU combining both in the same die. The PS3 still follows the usual architecture of separate GPU and CPU.
- Both Sony and Microsoft release the PS4 and Xbox One (and their future successors) with an APU combining both. The Xbox One is fed with DDR3 RAM (don’t know how many channels) + a fast ESRAM, and it seems the bandwidth was a huge problem for them and part of the reason why it performed worse than the PS4.
- Apple released the Apple-silicon powered Macbooks, shipping powerful GPUs inside the laptops on a single die. Powerful at the expense of being extremely big chips (see the M2 Max and Ultra), and maybe not as powerful as a 3070 mobile in most cases, but still quite powerful (and pricey, but I wonder if this is because of Apple or because APUs are, for the same performance level, more expensive, we’ll get to that).
- The Steam Deck is released, featuring a 4 cores/8threads CPU + RDNA2 GPU packed with a quad-channel DDR5 RAM at 5.5GHz, totalling 88GB/s.
Now, for price-sensitive products (such as the Steam Deck, or the other game consoles), APUs seem to be the way to go. You can even make powerful ones, as long as they have enough bandwidth. It’d seem to me that it’d be clear that APUs provide a much better bang for the buck for manufacturers and consumers, as long as they’re paired with a nice memory architecture. I understand desktop PCs care about upgreadability and modularity, but why is gaming APUs not a thing in laptops/cheap gaming OEM Desktops? With 16gb 4-channel DDR5 or even GDDR6 RAM, those things would compete really well against game consoles, while avoiding all the duplicated costs that are incurred in when pairing a laptop with a DGPU. And in the end, laptops already have custom motherboards, so what’s the issue at all? What are the reasons why even cheap gaming laptops pick RTX 3050’s instead of having some love from AMD?
Bonus question: How come the DDR3 RAM at 1066MHz in the Xbox One is 68.3GB/s while the Steam Deck, with a much newer 5500MHz RAM and quad-channel is able to provide just 88GB/s?
It’s actually the other way round.
APUs make sense in a power-constrained product, not a price-sensitive one.
The Steam Deck is a good example. It has a pretty weak CPU/GPU combo (4 Zen 2 cores and 8 RDNA 2 CUs), but this doesn’t matter, because what matters is being able to run games on battery for a decent amount of time.
When everything is on one chip, power requirements are lower, because there’s no need for inter-chip communication. Space is saved because there’s only one chip to use. This is great for small mobile products.
What about price?
APUs sell for cheap on the desktop because their performance is lower than other CPUs, but they aren’t cheap to make.
For example, Raven Ridge was 210 mm^(2), while Summit Ridge / Pinnacle Ridge were 213 mm^(2). So the chip price was about the same, but the Ryzen 1800X debuted at $500 and then dropped to $330, where the 2700X also sold, but the top of the range Raven Ridge, the 2400G, was sold for $170.
So even though it cost AMD the same to make these chips, Raven Ridge was sold for half the price (or a third for the 1800X). AMD therefore made a lot less money on each Raven Ridge chip.
The console prices are deceptive. Microsoft and Sony subsidise the consoles because they make money on game sales and subscriptions. The consoles are often sold at a loss. If the consoles were not subsidised, they’d have sold for double the price, and would have likely lost to a similarly priced PC.
Flexibility
Even though laptops aren’t user-expandable, they are still configurable. When it comes to gaming laptops, there are a lot of CPU/GPU combinations. It’s impossible to create a special chip for each combination, and binning is hardly enough to create them.
Without having separate CPUs and GPUs, you’d get an ecosystem similar to Apple’s, or the consoles, where there is a very small number of models available for purchase. That would kill one of the benefits of the Windows ecosystem, the ability to make your purchase fit performance and price targets.
A silver lining
Chiplets do make it possible to pair different CPUs and GPUs on the same chip, even together with RAM. You could call that an APU.
You’re probably the most right question. Thank you for your excellent insight. It makes total sense :)