I still want the first generation ASi Mac Pro to debut with M3 Ultra & M3 Extreme SoC options, on a daughtercard would be best for (limited) future upgradability...?
Daughtercards are not likely to get much future generation upgradablity. May be able to buy used parts in the future that are different daughtercard, but not likely to be able to get a M(n+1 or n+2 ) tray out of it.
Trying to subsume both what would have been "Northbridge" and "southbridge" chips onto the daughtercard isn't going to get deeper entanglements into the present that inhibit the future connectivity.
. But yeah a M2 Ultra/Extreme really don't make much economic sense at all, unless going to skip M3 generation and would have to squat on M2 until M4. The big chips are likely either on the 'odds' or 'evens' update sequence. M3,M5,M7 or M2,M4,M6 . A short cadence probably wouldn't work. The Mac Pro's don't upgrade that fast (for the Extreme) model. There is no product to 'hand me down" the Ultra/Extreme too once replacement them ( so even if churned the Mac Pro faster (i.e., every 12-16 months) they would have bigger problems recouping the investment).
The last three update cycles have been 3 years , 6 years , and at least 3 years. Every 1.5 (or less) years probably isn't happening. R&D costs too high and the run-rate of units
far, far, far too low to just throw these big SoCs out the window at a relatively rapid pace. To throw them away that fast, Apple would have to greatly increase the price and that would put the product just even deeper into a pricing death spiral.
Pretty good chance Apple's plan was either start the Mac Pro out on M1 (if everything went perfectly ... which by time pandemic started that was at deep threat ) or just wait until M3 to get started. M2 makes making an Ultra a bigger pain. The M2 chips are bigger and the M1 Max was about at the reticle limit for making a Ultra on InFo-LSI. It may be that they were going to switch to CoWos-LSI anyway for the Ultra. The Extreme would have to , since "two chips" was already at the limit. Even with N3 couldn't shrink that back down into InFo-LSI limits. And splitting the package tech R&D testing doesn't add much. N3 would help though in making both packages more manageable.
I also would like to see ASi (GP)GPU solutions rather than any third-party options, it seems like Apple would be reversing course after telling devs to optimize for pure ASi GPU cores for the past two+ years...
A ASi module with a huge NUMA overhead and/or non Unified memory would still be reversing course software wise. Wouldn't make a different if it has Apple sprayed on it or AMD , it is still a app software hiccup. And relatively tiny niche too.
A "mac on a card" would be far less of a break because there are some apps that distribute workload out to a cluster now. A "mac on a card" would be faster, simpler networking ( no wires , no switches , just plug it in and add a virtual Ethernet over PCI-e driver on both sides). No reversals in GPU driver semantics. Portable 'distribute to cluster" code that works on any Mac ( so relatively
vastly bigger market for the software vendors doing the work. ) .
I expect we will all find out more come WWDC at the latest...?
The last three WWDCs did absolutely nothing for plug-in GPUs. I wouldn't pins lots of hopes to WWDC. If Apple was going to release Mac Pro in June-October time frame then a limited , hands-off-just-look sneak peak could come this Spring
before WWDC comes. There is about zero upside in waiting until WWDC to do the reveal (presuming have the parts firmly contracted for and no huge showstopper bugs in macOS extensions for it ). That just reinforces that they are about over a year late delivering the Mac Pro. Squatting on it for an extra 2-3 months buys nothing. And if isn't ready to go for another > 6 months after WWDC there isn't much to say. There is a magical Goldilocks spot were the parts/software all perfectly align with WWDC, but that isn't very likely.
If Apple waits until WWDC to say anything , then there is probably something seriously broken and/or way off in the weed wrong with the Mac Pro. Mostly likely Apple was trying to target something in 2022 (perhaps late 2022) for the Mac Pro. It is a so discombobulated that the 'sneak peak' had to slide far more than 6 months ... it is seriously 'broke' somehow. And the let it get that deeply into a screwed up state is a bad sign for the long term.