commentzilla

blastdoor said:

It doesn’t matter how great apple’s designs are if they can’t manufacture them. 

Time to take diversification away from China into account at the design stage. “But can we build it in Mexico?” should be asked about every new design from now on.

programmer said:

My guess is that the Mac Pro will use the same M1 Ultra as the Mac Studio does.  The difference will be in the system around the SoC.  With a larger form factor, they have more cooling potential and could bump up the clock rates a little... but really, the M1 Ultra is a monster as it is (both in terms of size and performance).  I would just take what Turnes said at face value, this is already the last of the M1 series.  And I think we will see a Mac Pro that uses it.

So what could differentiate the Mac Pro?  In a word:  expandability.

1) PCIe slots.  The M1 Ultra seems to have plenty of I/O potential, and a fast PCIe bridge chip would easily enable a lot of expansion potential.

2) Drive bays.  The Mac Pro would have the same built-in super fast SSD, but in a large case a whole lot of additional storage can be accommodated.

3) RAM.  This is where it gets tricky.  The Apple Silicon approach is to use in-package memory, and there are real constraints on how much can be put into a single package.  Some Pros just need more than can be fit into a single package, or more than is worth building in the TSMC production run.  So conventional DIMMs are needed to supplement the super fast in-package memory.  The question is, how does OSX use it?  Apple seems to want to keep the programming model simple (i.e. CPU/GPU shared memory with a flat/uniform 64-bit virtual address space), so having some fast vs slow areas of memory doesn't seem like the direction they want to go in (although they could and just rely on the M1 Ultra's ENORMOUS caches).  They are already doing virtual memory paging to flash, however... so why not do virtual memory paging to the DIMMs instead?  Big DMA data transfers between in-package and on-DIMM memory across the very fast PCIe 5.0 lanes would ensure that the available bandwidth is used as efficiently as possible, and the latency is masked by the big (page-sized) transfers.  A 128GB working memory (the in-package RAM) is huge, so doing VMM to get to the expanded pool is not as bad as you might think.  Such a memory scheme may even just sit on PCIe cards so buyers only need to pay for the DIMM slots if they really need it.  Such "RAM disk" cards have been around for ages, but are usually hampered by lack of direct OS support... and issue Apple could fix easily in their kernel.