You seen this?
Predictions (I made on this sitethat Apple will release their own GPUs.
Also, user expandable RAM.
It is from back in March 2022. At the 3:30 mark he says he is 100% sure that the Mac Pro would be announced at WWDC (2022). That's where I stopped watching ( didn't really want to start watching in first place.).
I've punted on watching this for a while ( it has been cheerleader advertised on macrumors before ), but regretabily took a look.
Then goes onto talk lots about TSMC CoWos. But the Ultra doesn't use CoWoS packaging tech. Info_LSI. The four chip would have to, but Ultra isn't. Number of folks thought it used CoWos but later info showed Apple went another (more affordable ) path. Ultra Fusion is a very large interposer. It is a small interposer ( which is exactly in the diagrams at the beginning of the document so more than odd that he goes off on the CoWoS tangent if actually understood what he was looking at. )
The RAM isn't on the UltraFusion interposer in the Ultra. This Max die + UltraFUsion + substrate is stacked on another non chip "interposer"/substrate for the RAM connections.
The keep cool commentary at 11 mins is only talking about CPU TDP. The vast majority of the chip is a GPU, the CPU is misdirection fro the size and scope of the heat issues to be managed. Cleans it up later at the end of the video but why digging holes in the first place.
The part that talks about a secondary memory controller to 1TB of RAM also states that they secondary RAM source is slower RAM access times than the current Mac Pro. While better than paging to disk (even an SSD/Optane one) that is highly likely going to be quirky at best for general application allocation. Apple doesn't have deem NUMA support and that is definitely going to be "non uniform". If any real time latency constrain GPU data drifts out into that would be an even bigger problematical black hole. If there is a huge hiccup in access time then that secondary RAM as a RAM based SSD might be OK for largish data set ( e.g., static/immutable audio sample libraries , temporal scratch files , etc. ) makes sense. But for apps with multithreaded access with locking synchronization with wide deltas on lock acquisition... dubious Apple has that working well or will even make it work well longer term.
A SSD with DIMM slots would give something for the folks who want to tinker with something inside the box to fiddle with. However, folks who a > 1TB sized HPC computatation that they could throw at a modern Intel/AMD DDR5 ECC pool of completely homogenous RAM and > 64 threads ... why bother?
The notion of making the Max die even larger as a "feature" is also a head scratcher.... adding a second UltraFusion connect is going to displace some memory controller edge space. Doubtful bigger die is going to trade off for the memory edge space consumed. Perhaps the Thunderbolt and some other parts have been shipped off also (through "sub2" layer). And adding two more E cores isn't the core count "colossus" the hype train here is trying to make it out to be. Better than the M1 generation but that isn't going to be a Threadripper 5000 'killer'. Or make Ampere Computer 80 / 120 core solutions run away and hide in fear.
The 'Lifuka' codename fits the Ultra ( 2 Max dies). The GPUs cores from the 2nd die are 'remote' from the GPU cores on the first die. But they both belong to the same Ultra package. Same thing like Lifuka ( die ) is one of the islands of the country (package ) of Tonga. The iMac (in the iMac Pro case ) with an Ultra would have made sense. Apple went Studio with Ultra as a replacement for the iMac. That old leak was about an iMac which only embedded GPUs at best. The iMac 24" and Studio that Apple has delivered on have to separate GPU core only dies on them at all. Those are the iMac replacements. You've seen them ( 'Lifuka' has shipped). So a super head scratcher why that old "iMac is gonna have" rumor still is pushing the removable GPU card meme up the hill. Past the super secret code word decoder stage on the iMac transition products... Apple has crossed iMac off the transition 'to do' list and are on the Apple web pages now.
So not likely not really a "discrete" (as in removable) GPU. Apple has done nothing to move to support a GPU cores that are outside of a M-series package.