What custom processor options are available for the Apple Silicon Mac Pro? Is it possible to upgrade the processor after purchase?

At the time of initial system purchase, the Apple Silicon Mac Pro can be configured with either a 24-Core CPU/60-Core GPU or 24-Core CPU/76-Core GPU System on a Chip (SoC). EveryMac.com documents these configurations as the Mac Pro "M2 Ultra" 24 CPU/60 GPU and Mac Pro "M2 Ultra" 24 CPU/76 GPU, respectively.

As confirmed by iFixit in its customary teardown, just like all the other Apple Silicon Mac models, it is not possible to upgrade the processor or video processor in the Apple Silicon Mac Pro after purchase.

Photo Credit: iFixit (Apple Silicon Mac Pro Processor)

What type of RAM does the Apple Silicon Mac Pro use? Can it be upgraded?

Like all other Apple Silicon Macs, the Apple Silicon Mac Pro models all have "unified" RAM onboard that is integrated with the processor (SoC). It cannot be upgraded later, but all models can be equipped at the time of initial system purchase with more RAM than its default configuration, though.

The Apple Silicon Mac Pro has 64 GB of "unified" RAM onboard by default. At the time of system purchase, it can be configured with 128 GB or 192 GB of RAM for an additional US$800 or US$1600, respectively.

Of course, this is a radical downgrade from the Intel Mac Pro models that came before it -- the Mac Pro (2019) line -- which were equipped with only 32 GB of RAM by default but that also had a whopping twelve RAM slots and could be upgraded after the initial system purchase with as much as 1 TB or 1.5 TB of RAM.

It is worth noting that the inability to upgrade the RAM later likely will shorten the usable lifespan of the Apple Silicon Mac Pro compared to earlier models. If you can afford to configure your Mac Pro with more RAM than the default at the time of purchase, you should do so.