I'm very interested in it as well, I think we can mostly just speculate. I don't think it's a GPU, I think it's an independent SOC running some sort of real-time OS (https://en.wikipedia.org/wiki/Real-time_operating_system) I suppose it would necessarily have GPU cores in it to do image processing, but I don't think it itself is just a GPU, or gives any indication about discrete GPU's coming to the Mac. I think this is a very Vision-specific piece of silicon.
Edit: many are saying that is just an Image Signal Processor (https://en.wikipedia.org/wiki/Image_processor). I don't think that's quite the case because 1) The M-series chips are already known to have ISP's packaged into them. and 2) My understanding is that the R1's job is to provide continuity of passthrough even in the event of a kernel panic by the M-series chip. To my thinking, this means the R1 chip must have a level of independence beyond that of a traditional coprocessor. I think it is an entire SOC.
Alright, here's an idea for you: Vision Pro is shipping with the previous generation CPU. What if it was meant to ship earlier, but Apple's discrete GPU efforts got delayed? That could also explain why the M2 Mac Pro shipped without a discrete GPU, which is a glaring omission for that product.
1) There are plenty of pro users they can’t serve without discrete GPUs, since they’ll never have the power or transistor budget in an integrated offering that would allow them to compete with AMD and Nvidia.
2) Why do a Mac Pro that doesn’t support discrete GPUs when the Mac Studio exists?
3) They’re doing hardware stuff in the M3 GPU that indicates a fairly serious GPU effort.
4) If they’re willing to put this much effort into a co-processor for a low-volume experimental product, putting similar effort into a co-processor (discrete GPU) for high volume sure-thing products (Pro laptops and desktops) seems at possible.
Put a discrete GPU and most of the magic of unified memory goes out the window. The M3 Ultra should be able to use up to 256GB of high bandwidth RAM. That blows away any discrete GPU. Yes, it doesn't have the processing power of a dedicated professional Nvidia card but I don't think Apple is trying to compete there. Apple is trying to fill the high VRAM niche. They might have a real advantage there considering LLMs require a ton of memory.
If Apple ever makes an "M3 Extreme" by gluing 4x Max dies together, they could have up to 512GB of VRAM. You'd need to 7x H100 GPUs to match total RAM size which will cost you $210k.
I heard a really sad report (via anonymous apple employee on the podcast ATP.fm, I'll try to find the episode) that they have totally canned the "Extreme" i.e 4xMax project entirely, for at least the next several revision cycles.
You're arguing that they could and should bring back support for discrete GPU's, which I don't disagree with at all. What I'm saying is, I just don't think they are going to, in the near future.
Edit: many are saying that is just an Image Signal Processor (https://en.wikipedia.org/wiki/Image_processor). I don't think that's quite the case because 1) The M-series chips are already known to have ISP's packaged into them. and 2) My understanding is that the R1's job is to provide continuity of passthrough even in the event of a kernel panic by the M-series chip. To my thinking, this means the R1 chip must have a level of independence beyond that of a traditional coprocessor. I think it is an entire SOC.