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MP All Models Is the Apple SoC Mac Pro vaporware?
- Thread starter DearthnVader
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There is little need for the Apple Silicon Mac Pro to have RAM slots. Memory can be expanded with CXL memory module over the PCIe bus.
Using a PCIe Slot to Install DRAM: New Samsung CXL.mem Expansion Module
www.anandtech.com
CXL memory is not completely 'transparent' to applications as the main memory is.
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Pramatically, it pretty much requires being at PCI-e v5 level. Apple has shown no signs of wanting to chase that level any time soon. Further, CXL isn't technically part of the PCI-e standard. It is a seperate protocol that is run over PCI-e physical layer, but the upper levels of the PCI-e protocol. So it requires support on both ends (again Apple would have to step up to another protocol they have shown little outward afinity toward. Apple isn't a memory of CXL consortium. Apple is in AV1 and haven't seen anything out of them for hardware support from them, but at least putting up a 'front' that they are 'on board'. CXL? Nothing. ).
It is better than accessing data on a Optane like DIMM ( non-volatile memory, NVM), but looking at about double the latency (if you are lucky).
Apps that have highly ingrained assumptions that everything is completely uniform latency tend to run into issues when grossly violate their assumptions. All apps won't break , but some likely would.
For example some app code that mapped some 'unified' memory for GPU work that somehow got migrated to CXL and exhibited far more pronounced NUMA artifacts probably would not go over well.
The server vendors that are lining up to use CXL are going to tap dance around the different latency problem.
"...
On the software side, the solution is quite ingenious. Microsoft often deploys multi-socket systems. In most cases, the VMs are small enough that they just fit on a single NUMA node entirely, cores and memory. The hypervisor at Azure attempts to place all core and memory on a single NUMA node, but In some rare cases (2% of the time), a VM has a portion of resources spanning across the socket. This is not exposed to users. ..."
CXL Enables Microsoft Azure To Cut Server Capital Expenditures By Hundreds Of Millions Of Dollars
Microsoft's first generation memory pooling with CXL can significantly reduce the amount of DRAM needed for servers. Up to 25% of DRAM is stranded, and 50% of VMs never touch 50% of their memory. Reducing overprovisioning and underutilization with CXL pooled memory "represents hundreds of...
www.semianalysis.com
The 'whole app' ( in their context a whole virtual machine) is pointed at the CXL memory pool. If uniformly slower it will still be "uniform".
The major CXL application is completely opposite of applying the 'more remote' RAM as a single pool to a single end user application.
".. At Azure, we find that a major contributor to DRAM inefficiency is platform-level memory stranding. Memory stranding occurs when a server’s cores are fully rented to virtual machines (VMs), but unrented memory remains. With the cores exhausted, the remaining memory is unrentable on its own, and is thus stranded. Surprisingly, we find that up to 25% of DRAM may become stranded at any given moment. ..."
same article.
as opposed to folks trying to load a single 400GB large dataset into memory and chomp on it will all the cores inside the box in a united 'attack on the data'.
macOS does already have some built-in mechanism of identifying 'lightly' or 'unused' data in RAM and compressing it. For example folks who load in 20GB of sound samples and then proceed to only use some 2GB subset for the next 4 hours. Hugely wasteful, but macOS will try to tap dance around that excessive disuse. CXL could be used as a RAM SSD that they macOS 'compress unused stuff' could shovel stuff into that would free up more primary RAM than compressing the data will. (for example if it is already highly compressed data... trying to compress it some more isn't going to work so well. But if could toss that stuff into some more external, slower pool that would greatly help. It really isn't being actively used anyway. That would be a much closer match to the 'stranded memory' problem. )
It isn't just minimal CXL . These memory cards need Type 3 CXL that has two possible pieces of the standard. cxl.io , cxl.memory.
CXL could be helpful also though in making 3rd party GPUs appear more "Unified memory", but not quite "Uniform access , Unified memory". Apple states they have "Unified Memory" but it appears it is more so "Uniform, Unified , High Performance Memory" is actually closer to what they are basing lots of internal assumptions on. CXL for GPU cards would 'close the gap' to being closer to "united" ( just falling a bit short on Uniform access. )
[ instead of somewhat clunky PCI-e 'resizable bar' , there would be something that was more cache coherent by design. This is what is probably going to trickle down to the higher end consumer desktop SoC and GPUs over in a generation or two. When it triclkles down I think Apple might feel more 'heat' to intercept it. Short term ( M2 and M3 ) it would not be surprising to see Apple 'punt' on CXL. They are not a member of the consortium , so overtly seem to be very disinterested. While CXL is confined to very expensive server parts they probably will ignore it. ]
The problem with classifying them with a 'vaporware' tag is that Apple really isn't doing much to 'advertise' the next Mac Pro at all. The notion of "we'll transition the whole line up in about two years" is an extremely obtuse way to refer to the Mac Pro. It is all indirect. The equally say something by saying almost nothing reference to " .. Mac Pro on another (later) day " is a statement of about to as much of nothing as possible.
Classic vaporware is where a vendor goes out of their way to 'advertise' or 'talk up' various aspects of the new product that are 'insanely great'. Faster than xxx competitor. More fun to play than foobar's other game. etc etc.
Apple is saying next to nothing about specific about the Mac Pro at all. That is actually what you are complaining about 'seeing nothing'. no rigged demo . no details ... basically nothing.
Apple Airpower is/was a much more suitable 'product rollout' to tag with 'vaporware' than the next Mac Pro so far. In case, Apple did get on stage and make a 'big deal' about their product. ' Charge three devices at one time better than any other device... just toss it on he mat willy-nilly and it will automagically charge. ' Full P.T. Barnum treatment ..... and never shipped. That's vapourware.
'Apple wont' outline future roadmap features' vs. 'Apple primarily corporate policy against talking about future products' isn't a 'vapourware' issue. It is more a philosophical disconnect than "over promise and under deliver".
Highly doubtful Apple has a poster on the wall saying " 1 TB of RAM or bust". They don't have a good path to ECC let alone anything over 200GB of RAM.
Apple didn't 'feature match' the other desktops they moved to Apple silicon. The M1 Mini topped out at 16GB while the 2018 Mini topped out at 64GB . Feature match a 'must have' critieria? No. Even the new M2 Pro Mini that finally decommissioned the remaining Intel Mini still stops at half that old 'high water' mark; 32GB.
iMac 24 ... same issue (because same M1 SoC).
iMac 27" ... similar M1 Max caps out at 64GB. (also half of 128GB)
Why the expectation that the Mac Pro is going to be held to some "have to match Intel model" standard on RAM was going to be an 'issue' at all. They just were not.
I think Apple has a handle on just how large of the Mac Pro user base is actually using anything over 200GB of RAM or not.
The > 1TB RAM was a 'free' feature of the Xeon W-6200 that apple used. It just kind of came along for the ride. In fact, there were multiple thousand dollar cheaper 28 24 core options that did not go over 1TB and Apple completely skipped those BTO options on purpose. Apple slaps an Apple tax on top of Intel CPU prices. So a tax on tax of a higher number just brings Apple more revenue. They were at least as much chasing profits as much as RAM capacity (if not more).
I suspect Apple is going to shift the "max RAM" metrics over to VRAM capacity from EEC RAM. If two W6800X Duos have 128GB of VRAM then if the new Mac Pro has 128GB (or more) of Apple's 'poor man's HBM RAM' that will counted as a 'win' on feature parity. For some subset of workloads that is a 'win'.
Apple isn't doing much at all to 'paralyze' folks. There are a large number of folks paralyzing themselves, but Apple is doing next to nothing in actively persuading folks to do so.
This is not 'classic vaporware' at all. Classic vaporware involves an overtly active campaign to talk about the product. Apple isn't. The "about two years we will transition" is almost completely obtuse reference to the Mac Pro. Mac Pro isn't being mentioned in the slightest. There is a huge amount of reader inference by some actively trying to loop the Mac Pro into that reference, but Apple is playing about zero active role there in doing that.
Similar to the "Mac Pro another (later) day" is also largely just an hugely obsure reference to the Mac Pro. There is next to 'nothing' there. "The Mac Pro will be faster than a blah blah banana Jr 9000" ? Nope. It will have X and Y? Nope. There is really no details or any kind of 'sales pitch' there at all. You have to sales pitch something for it to be vaporware. No sales pitch, no 'vapor'.
Apple Airpower. Vaporware. Apple got on stage and explitcity said it was going to have features that no other wireless charger ever had. They gave it the full P.T. Barnum treatment ..... and shipped nothing. That's classic vaporware.
The primary people constantly yapping about how great the new Mac Pro is going to be is Rumor sites and tech journalists looking for clicks to drive ads/attention. But that isn't Apple talking. That is other folks filling in the information vacuum. That is a substantively different issue than 'vaporware'.
It was a statement by an Apple executive during an official Apple launch event that the Mac Pro Apple Silicon is coming. No it wasn’t the launch of the machine, but neither was I’d total silence on it or denying it exists. The only computer Apple has really ever spoken about before it’s launch is the Mac Pro, they even stated a totally new one was coming I think a year or two before the 2019 model was launched.