Micron Ships Crucial-Branded LPCAMM2 Memory Modules: 64GB of LPDDR5X for $330(anandtech.com)
anandtech.com
Micron Ships Crucial-Branded LPCAMM2 Memory Modules: 64GB of LPDDR5X for $330
https://www.anandtech.com/show/21390/micron-ships-crucialbranded-lpcamm2-memory-modules
73 comments
LPCAMM is the best thing to happen in the laptop space since Framework. Forget Apple's ridiculously expensive soldered storage and memory; LPCAMM is a step in the right direction.
That was true when they had Intel CPU's and soldered the RAM chips on the board.
Now they have the memory chips "inside" the "CPU", aka: system in a package.
Big Tim is way ahead of the game when it comes to ruthless product targeting and segmentation.
Now they have the memory chips "inside" the "CPU", aka: system in a package.
Big Tim is way ahead of the game when it comes to ruthless product targeting and segmentation.
Apple's ridiculously expensive fast & wide on-package memory is a big reason why the M series chips are so fast. Expect AMD & Intel to adopt a similar strategy in their high end chips soon.
Intel is already there at the ultra-high-end, the Xeon Max is a hybrid with 64GB of HBM2 on-package and an external DDR5 bus supporting up to 4TB of socketed RAM. The HBM2 can be configured to work as L4 cache for the DDR5, or it can boot without any DDR5 at all and run entirely from the HBM2.
https://www.servethehome.com/intel-xeon-max-9480-deep-dive-i...
https://www.servethehome.com/intel-xeon-max-9480-deep-dive-i...
I remember seeing this from STH as well, and my first thought was "I want one of these in my laptop!" It'd be perfect then to max ram in a laptop with 2 sodimm slots, or one of these 64gb lpcamm's. Ideally with a thinner laptop in mind, but probably not with the heatsink for THAT massive xeon.
I really hope the hbm memory on-die trickles down into pro-sumer processor chips eventually too.
I really hope the hbm memory on-die trickles down into pro-sumer processor chips eventually too.
Intel's Lakefield also comes to mind, pretty underrated chip imo. The first x86 big/small heterogenous chip, using Intel's Foveros to stack memory, CPU, and platform chip into one package. It made for a very simple design that just needed power. LPDDR4X-4266 doesn't crazy fast but in 2020 it was pretty swift. https://www.anandtech.com/show/15877/intel-hybrid-cpu-lakefi...
Alas the 1+4 Skylake+atom were all pretty meh chips & Intel hasn't tried again. Conceptually I really.liked it, and it was doing great against the Qualcomm 8cx competitor for the tablets/2-in-1s it was in, but people wanted more.
Alas the 1+4 Skylake+atom were all pretty meh chips & Intel hasn't tried again. Conceptually I really.liked it, and it was doing great against the Qualcomm 8cx competitor for the tablets/2-in-1s it was in, but people wanted more.
MI300X also has on-package RAM, but that's even further from a laptop chip than Xeon Max. :)
> Apple's ridiculously expensive fast & wide on-package memory is a big reason why the M series chips are so fast
Increasing memory speeds have had only a marginal impact on common workloads (not AI) in the PC World - this has been a well discussed topic. Why would it be different on the Mac?
Increasing memory speeds have had only a marginal impact on common workloads (not AI) in the PC World - this has been a well discussed topic. Why would it be different on the Mac?
probably something to do with rounded rectangles
Memory speed usually refers to memory bandwidth, which does have a limited amount of impact on day to day apps as they don't usually require a lot of bandwidth.
Memory Latency, on the other hand, can have a huge impact on performance. That's the reason chips have had steadily increasing cache sizes over the decades along with the introduction of additional caching layers.
What Apple's M series improves by putting the memory on chip is both bandwidth and latency. The latency, however, is what will impact app performance more than anything else.
Latency improvements are the reason memory controllers were moved from motherboard northbridges into the CPU IC. Shortening that distance means a lot to shortening latency.
Memory Latency, on the other hand, can have a huge impact on performance. That's the reason chips have had steadily increasing cache sizes over the decades along with the introduction of additional caching layers.
What Apple's M series improves by putting the memory on chip is both bandwidth and latency. The latency, however, is what will impact app performance more than anything else.
Latency improvements are the reason memory controllers were moved from motherboard northbridges into the CPU IC. Shortening that distance means a lot to shortening latency.
Amusingly the top-line latency number is higher than for X86, but I agree with you because that number hides the better performance in other latency metrics that are probably more important.
It's not about memory bandwidth. [1] shows that M1 is 66x faster at pointer chasing than an equivalent AMD. You can look at [2] and [3] to see that TLB penalty is also lower at any given test depth which is important because TLB misses aren't that infrequent and they're serial in your ability to access any memory that's not in your cache.
It's not an unreasonable hypothesis that this is because of on-package memory which means you can run with tighter thresholds since your memory traces are shorter. Their unified memory architecture also means that GPU is way more effective since you never need to copy memory from the CPU to GPU. That's probably not a huge deal for normal apps, but having rendering the screen not competing with any app resources for memory probably isn't nothing.
Neither the CPU nor the GPU can fully utilize the available memory bandwidth [4] The insane memory bandwidth is to also support the other coprocessors like the media engine & to ensure that you can do a bunch of tasks in parallel without them contending with each for resources. Those workloads do benefit greatly from memory bandwidth & the "artist" community is hugely important to Apple.
The reason M is overall faster is more because of things like better ILP (e.g. fixed-width RISC encoding vs compression-like CISC means easier to keep the pipeline fed). Apple software for the most part is better engineered for performance & the M chip is optimized for that performance profile (e.g. C# and Java vs Swift/ObjC - Rc is pretty conclusively faster & requires less memory overall not to mention that the M chip has specific optimizations to further reduce the traditional cost of Rc that they have to pay because they don't typically distinguish Rc from Arc as Rust does). The final truth is that Apple throws a lot of money at this problem as well & buy up the latest processing node to stay ahead of the competition.
[1] https://www.linkedin.com/pulse/apple-m-cpus-probably-much-fa...
[2] https://www.anandtech.com/show/16252/mac-mini-apple-m1-teste...
[3] https://www.anandtech.com/show/17047/the-intel-12th-gen-core...
[4] https://www.anandtech.com/show/17024/apple-m1-max-performanc...
It's not an unreasonable hypothesis that this is because of on-package memory which means you can run with tighter thresholds since your memory traces are shorter. Their unified memory architecture also means that GPU is way more effective since you never need to copy memory from the CPU to GPU. That's probably not a huge deal for normal apps, but having rendering the screen not competing with any app resources for memory probably isn't nothing.
Neither the CPU nor the GPU can fully utilize the available memory bandwidth [4] The insane memory bandwidth is to also support the other coprocessors like the media engine & to ensure that you can do a bunch of tasks in parallel without them contending with each for resources. Those workloads do benefit greatly from memory bandwidth & the "artist" community is hugely important to Apple.
The reason M is overall faster is more because of things like better ILP (e.g. fixed-width RISC encoding vs compression-like CISC means easier to keep the pipeline fed). Apple software for the most part is better engineered for performance & the M chip is optimized for that performance profile (e.g. C# and Java vs Swift/ObjC - Rc is pretty conclusively faster & requires less memory overall not to mention that the M chip has specific optimizations to further reduce the traditional cost of Rc that they have to pay because they don't typically distinguish Rc from Arc as Rust does). The final truth is that Apple throws a lot of money at this problem as well & buy up the latest processing node to stay ahead of the competition.
[1] https://www.linkedin.com/pulse/apple-m-cpus-probably-much-fa...
[2] https://www.anandtech.com/show/16252/mac-mini-apple-m1-teste...
[3] https://www.anandtech.com/show/17047/the-intel-12th-gen-core...
[4] https://www.anandtech.com/show/17024/apple-m1-max-performanc...
No. M1/2/3 has data memory-dependent prefetcher[0] which can speculatively chase pointers in contiguous memory ranges, reducing indirection cost provided the data there is homogenous, looks like pointers and prefetch attempts are successful per cache line. It also has extra good indirect load predictor.
These have little to do with memory packaging and a lot to do with cache and prefetching architecture.
It does have one of the lowest latencies for atomics[1][2] which is something Swift cares about, but the overall core design just as much benefits other, less indirection and synchronization heavy languages (side note: Swift and Java are closer with each other in defaulting to virtual dispatch, where-as C# sits in the middle of the road with static dispatch by default but some code heavily using interfaces and virtual methods which do make such calls virtual to an extent (JIT has DPGO to devirtualize, AOT can uncoinditionally devirtualize in certain scenarios too, similar to what Swift's WMO does)).
[0] https://gofetch.fail/files/gofetch.pdf
[1] https://dougallj.github.io/applecpu/measurements/firestorm/D...
[2] https://dougallj.github.io/applecpu/measurements/firestorm/C...
These have little to do with memory packaging and a lot to do with cache and prefetching architecture.
It does have one of the lowest latencies for atomics[1][2] which is something Swift cares about, but the overall core design just as much benefits other, less indirection and synchronization heavy languages (side note: Swift and Java are closer with each other in defaulting to virtual dispatch, where-as C# sits in the middle of the road with static dispatch by default but some code heavily using interfaces and virtual methods which do make such calls virtual to an extent (JIT has DPGO to devirtualize, AOT can uncoinditionally devirtualize in certain scenarios too, similar to what Swift's WMO does)).
[0] https://gofetch.fail/files/gofetch.pdf
[1] https://dougallj.github.io/applecpu/measurements/firestorm/D...
[2] https://dougallj.github.io/applecpu/measurements/firestorm/C...
Yeah. But even as a NUMA area, upgradability would win a lot of brownie points here (of course modern Apple does not give a flapping bird about it)
Not sure how it works on the iMac/MacPro
Not sure how it works on the iMac/MacPro
Would love to see a Mac Pro with 8 of these…
Soldered? It's not soldered. It's part of the actual SoC. Could we please update our research to more recent than 20 years ago?
It's soldered to the package. The actual RAM components are the very same discrete BGA ICs that would normally be soldered to a motherboard, but they've soldered them right next to the SoC die instead for tighter signaling.
https://i.imgur.com/Y3PLp33.jpeg
Anyway results are what matters, and the module in the OP has bandwidth figures half way between the M3 and M3 Pro while retaining upgradability.
https://i.imgur.com/Y3PLp33.jpeg
Anyway results are what matters, and the module in the OP has bandwidth figures half way between the M3 and M3 Pro while retaining upgradability.
The switch to ARM Macs only happened 3.5 years ago, plenty of Intel models still in service that would benefit from a RAM upgrade if it weren’t soldered
The ram is soldered into an Intel Mac for the exact same reason that it's soldered into an ARM Mac.
To make upgrades incredibly expensive, allowing them to have the same product generate revenue as both an expensive mid-range machine as well as a ridiculously expensive "professional" machine. Why make different products when you can sell the same product at different prices?
In case of intel macs, the soldered RAM should have made the device and RAM options even cheaper, as the BOM is simpler. The only real argument against soldered RAM was DDR5 in SODIMM being bad - which LPCAMM2 fixes.
If they didn't use it specifically to price gouge, the soldered RAM wouldn't have been a problem. 64GB of RAM costs practically nothing at market prices, so they could honestly have had a single SKU with max RAM without notable price change over entry level - heck, maybe the BOM reduction would even sponsor it.
... But then they'd lose their mechanism to drain companies with deep pockets for necessary upgrades. Being sensible and fair is not profitable.
In case of intel macs, the soldered RAM should have made the device and RAM options even cheaper, as the BOM is simpler. The only real argument against soldered RAM was DDR5 in SODIMM being bad - which LPCAMM2 fixes.
If they didn't use it specifically to price gouge, the soldered RAM wouldn't have been a problem. 64GB of RAM costs practically nothing at market prices, so they could honestly have had a single SKU with max RAM without notable price change over entry level - heck, maybe the BOM reduction would even sponsor it.
... But then they'd lose their mechanism to drain companies with deep pockets for necessary upgrades. Being sensible and fair is not profitable.
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iFixit did a video about it:
https://www.youtube.com/watch?v=K3zB9EFntmA
https://www.youtube.com/watch?v=K3zB9EFntmA
So if I understand correctly the new format has performance benefits, partly due to shorter traces and a better connection to the motherboard. So would this format eventually come to desktop too?
From my limited understanding, the specific performance benefits in the article come from it being DDR5X memory. LP (Low Power) DDR needs to be very close to the CPU (short traces) because of how much less power it consumes. DDR5x should have the same bandwidth as LPDDR5x, it would just consume more power. Up until now, there wasn't a way to have "socketed" LPDDR, so it was soldered to the motherboard or even placed in the same package as the CPU (Apple M-series CPUs have the RAM in the same package as the CPU). Now they have a standard way to basically strap down a BGA chip that will live right next to the CPU.
DDR5x isn't a thing. LPDDR memories and DDR memories have a significant differences in how the interface works; LPDDR isn't just a low-voltage version of DDR, and it's mostly coincidental that the generation numbering lines up (as opposed to DDR vs GDDR generation numbering).
Ah, I didn't know LPDDR and DDR were fully different things! I always assumed since their generation numbers lined up they were based on each other.
I think this is performance relative to SO-DIMMs, not relative to desktop/server DIMMs.
Performance benefits versus other replaceable RAM. It's still a small (on the order of 10%) regression from the on-die RAM that Apple has been popularising
in-package ram is certainly not an apple thing. if anything, it's a phone thing.
Indeed, but I don't know of any other PC manufacturers who were widely using it before Apple went down the soldered-RAM path?
I'll get excited when I see the 128gb LPCAMM's out. It's tough to find a laptop with 4x slots to do 128gb, best option was a lenovo t15g with an 11th gen intel, but it's a pretty fat thing to have to carry. Luckily mine mostly stays home a stand.
Even 2 of these is better than having to fit 4 sodimm slots to now, but I'd really rather an ultra slim with 128gb.
Even 2 of these is better than having to fit 4 sodimm slots to now, but I'd really rather an ultra slim with 128gb.
This appears to sacrifice more horizontal space, I don’t see this coming to desktops in its current incarnation as motherboards are already super cramped and replacing 4 ram slots for one doesn’t seem like a trade off most users are willing to make.
Maybe it's thin enough that you could squeeze it onto the back side of the motherboard? It would be annoying to build that way, but there's plenty of space there.
It may be annoying to assemble the machine with memory modules on the back of the board, but as far as manufacturing the board this connector is ideal for putting memory on the back: it's just exposed pads on the motherboard, no soldered connector. So it's even simpler to manufacture than something like putting a M.2 slot on the back.
> replacing 4 ram slots for one doesn’t seem like a trade off most users are willing to make.
Having four slots on consumer motherboards is already nearly vestigial in the DDR5 era: two slots is already enough to hit 96GB (128GB later this year), and filling all four slots with dual-rank modules comes with severe speed penalties. Buying a single module rather than a kit with a matched pair is an improvement for consumers. The main sacrifice with LPCAMM2 is losing the ability to reach a quad-rank configuration. But the current limit of 64GB with LPCAMM2 for a mainstream processor with a 128-bit memory bus is definitely sufficient for most consumer desktops, including basically any gaming desktop.
Having four slots on consumer motherboards is already nearly vestigial in the DDR5 era: two slots is already enough to hit 96GB (128GB later this year), and filling all four slots with dual-rank modules comes with severe speed penalties. Buying a single module rather than a kit with a matched pair is an improvement for consumers. The main sacrifice with LPCAMM2 is losing the ability to reach a quad-rank configuration. But the current limit of 64GB with LPCAMM2 for a mainstream processor with a 128-bit memory bus is definitely sufficient for most consumer desktops, including basically any gaming desktop.
Is LPCAMM2 just a new form-factor, kinda like 2.5" drives to m.2 drives, or is there some leap in how it works? I don't quite get if the "C" in CAMM is for data compression or just it's 'physically' compressed.
It enables shorter traces between the CPU and memory chips which allows for higher speeds compared to the traditional SO-DIMM form factor. And the compression is physical (the socket works like modern LGA CPU sockets).
Compression describes how it is physically attached. Similar to desktop CPUs, LPCAMM maintains contact with the mobo via screws that apply a consistent pressure to the module, ensuring a completely solid connection.
There is no preceding form factor that LPCAMM2 will replace. It's the first standardized removable module for LPDDR. Prior to this, LPDDR has only been usable in soldered-down packages.
Emphasis on 'standardized' -- the 2 in LPCAMM2 is indeed meant to refer to the second generation of LPCAMM, but it's the first generation that has been approved as a JEDEC standard (and therefore, the first one that most people will be able to buy).
Was the original CAMM from Dell ever used with LPDDR, or just DDR5?
LPCAMM2 = Low Power Compression Attached Memory Module 2
So the compression in this case is physical.
So the compression in this case is physical.
wonder when/how this will be used in desktop and server contexts - the mounting/shape seems to emphasize planar area. with current servers needing 12 channels/socket, is there space for 12x LPCAMM in even a standard 1U dual-socket server?
Rumor has it that AMD is pushing a 256b memory interface in Strix Halo, perfect for 2x LPCAMM: we might see some exciting developments in desktops as well.
Rumor has it that AMD is pushing a 256b memory interface in Strix Halo, perfect for 2x LPCAMM: we might see some exciting developments in desktops as well.
Is Strix Halo launching on desktops? I'd have assumed that the 256b bus would restrict it to a unique socket.
being desktop doesn't imply AM5. there was a 4-channel threadripper, for instance.
but I was thinking more of a mini-pc, since legacy form-factors don't make that much sense for a high-end APU. being a mini-pc would also make it more palatable to solder on the CPU like a laptop - and of course soldered-on RAM gets to run at higher speed.
but I was thinking more of a mini-pc, since legacy form-factors don't make that much sense for a high-end APU. being a mini-pc would also make it more palatable to solder on the CPU like a laptop - and of course soldered-on RAM gets to run at higher speed.
Threadrippers exist, but would Strix Halo then use Threadripper sockets? Would it use its own sockets? I don't expect Strix Halo to appear in any socketed form.
I think you're right that it'll appear in SFF PCs, like most of AMD's mobile parts do. And that is pretty exciting IMO.
I think you're right that it'll appear in SFF PCs, like most of AMD's mobile parts do. And that is pretty exciting IMO.
So roughly a 12% performance loss using LPCAMM2 vs soldered to the motherboard. Reasonable tradeoff, I guess, for future expansion.
How much extra is the cost (in todays prices)?
How much extra is the cost (in todays prices)?
> So roughly a 12% performance loss using LPCAMM2 vs soldered to the motherboard.
If you're getting that from the fact that these modules run at ~7500MT/s while there are BGA packages rated for 8500 MT/s: the limitation is not from the LPCAMM2 connector, but from the fact that Intel and AMD don't have memory controllers capable of going beyond 7500MT/s yet. The 8500MT/s memory is being used for smartphones that can hit those speeds, and it would be a waste to put the faster memory on LPCAMM2 modules right now. They're planning to eventually reach 9600MT/s with LPCAMM2, but don't expect to see those modules on the market when there's literally zero demand for them at those higher speeds.
If you're getting that from the fact that these modules run at ~7500MT/s while there are BGA packages rated for 8500 MT/s: the limitation is not from the LPCAMM2 connector, but from the fact that Intel and AMD don't have memory controllers capable of going beyond 7500MT/s yet. The 8500MT/s memory is being used for smartphones that can hit those speeds, and it would be a waste to put the faster memory on LPCAMM2 modules right now. They're planning to eventually reach 9600MT/s with LPCAMM2, but don't expect to see those modules on the market when there's literally zero demand for them at those higher speeds.
64gb is an impressive amount to fit on an LP. Come to think of it, I should back up my ZX Spectrum magnetic tapes to LPs for archival storage.
Wonder if this would potentially allow for swappable memory in GPU cards. Might be suitable for midspec GPUs.
All of the current-generation discrete GPUs from NVIDIA and AMD (desktop and laptop parts) run their memory at over twice the per-pin bandwidth of these modules, and some over three times the speed. The roadmaps for LPCAMM2 indicate it's expected to work at least up to 9.6Gbps memory, but for GPUs it would have to go beyond 20Gbps.
Are there applications where having more, but slower memory, would be useful for GPUs? Tiered storage for GPUs?
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