The forthcoming Mac Pro is reportedly unlikely to add support for GPU PCI-E cards, as well as not allowing user-upgradeable RAM.
Apple Silicon Macs have lacked support for external GPUs from the start. Now it appears that the M2 Mac Pro cannot change that.
According to Bloomberg's Mark Gurman, the Mac Pro "may" lack upgradeable GPUs, and this adds to its expected lack of modularity and expansion options.
The next Mac Pro may lack user upgradeable GPUs in addition to non-upgradeable RAM. Right now Apple Silicon Macs don't support external GPUs and you have to use whatever configuration you buy on Apple's website. But the Mac Pro GPU will be powerful with up to 76 cores.
— Mark Gurman (@markgurman) January 26, 2023
"That will leave storage as the main user-upgradeable component in the new Mac Pro," continues Gurman, "which will have the same design as the current, Intel model."
"The big difference between a Mac Pro and a Mac Studio — in addition to M1 Ultra to M2 Ultra," he says, "should be performance from more cooling."
It's been previously reported that the Mac Pro will not allow after-market RAM upgrades, because the memory is part of the Apple Silicon processor.
While the Mac Pro remains on Intel processors, there are circumstances where this most expensive Mac can be effectively equaled by the lowest-cost one, the Mac mini.
55 Comments
If Gurman hadn't used the specific number "76", I wouldn't have put much credence in his prediction. The lack of expandable RAM is expected. The claim that it "may lack an upgradeable GPU" is completely true: it may lack one. It may also lack an Apple sticker.
One way this 'may' play out is that you can't have a PCI-e GPU in the sense of a card into which one can plug a monitor. But perhaps you *can* have a PCI-e accelerator card, and if that accelerator happens to have some RDNA3 chiplets, well so be it.
But I wouldn't be surprised if Apple really doesn't support GPUs in any form at all. They have made *such* a big deal out of the benefits of shared memory between the CPU and GPU. I'm inclined to think they really mean it. I really wonder if the next step for the M series will be distinct CPU and GPU chiplets connected by UltraFusion, thereby allowing pro users to better pick the right balance of CPU and GPU power for their needs. The vast majority of volume might still be fully integrated, single die SOCs, but for the 'pro' market splitting CPU and GPU onto different chiplets could be the way to go.
I know people might say they won't do it because of low volume, but I don't think that's such a big issue. These hypothetical 'pro' chiplets would still have the same CPU, GPU, and NPU core designs, so they benefit from economies of scale there. It's the 'glue' (UltraFusion) that's really unique, but Apple has already shown a willingness to do that in small volumes. Plus, 'pro' customers are accustomed to paying a ton for high-end chips -- those Xeons ain't cheap.
Obviously no traditional RAM, but many workflows that require that can already use RAM disks and virtual memory.
I think part of the GPU story is being missed, but we will see. Apple knows they have a hole to fill in preview rendering and they have been putting a lot of effort in to making metal ready on the software side. No idea what the plan is, but I wouldn’t be surprised if they create some type of rendering acceleration card that might not work as a normal GPU. I can’t imagine they will say they have the embedded GPU– end-of-story. As great as that GPU is, it isn’t quite powerful enough for people buying $50K machines which need a minimum 4X more GPU performance. I’ve thought that either they are getting AMD support for compute or maybe something out of the 2020 partnership with Imagination Technologies. Imagination has been helping with hardware ray tracing. Maybe they also have an ace up their sleeve. Originally Apple was building a discrete GPU for these machines code named Lifuka, but it was rumored to have been canceled for being too slow at the tasks it needed to perform. The Imagination contract was signed pretty close to the time that GPU was rumored to have been canceled. This is all conjecture, but I think we will see a surprise when the Mac Pro is launched.
So much for modular design and now back to square one. This is going to be Mac trash can, the 2013 Mac Pro, all over again. Oh brother.
Considering that so far there’s been zero evidence of a PCIe interface in Apple Silicon, this has seemed obvious for a very long time. Of course, everything being within Apple’s control, they could surprise us with a Pro-specific SoC sporting a PCIe interface. But that really breaks the performance and memory advantages of unified memory, so I’m very doubtful.