I suppose in fairness and to the explanation it does give, the other thing that footprint allows is a shorter path for the pins that would otherwise be near the ends of the daughter board (e.g. on a DIMM), since they can all go roughly straight across (on multiple layers) instead of a longer diagonal according to how far off centre they are. But even if that's it, that's what I mean by it seeming incomplete. :)

All the traces going into the slot need to be length-matched to obscene precision, and the physical width of the slot and the room required by the "wiggles" made in the middle traces to length-match them restrict how close you can put the slot. Most modern boards are designed to place it as close as possible.

LPCAMM2 fixes this by having a lot of the length-matching done in the connector.

And all this is needed even though the DRAM signaling standard has extensive measurement and analysis of the traces built right into the hardware of the DRAM and the memory controller on the processor. They negotiate the speed and latency at runtime.

Giant pain.

From what I gathered, it's around a watt per when idling (which is when it's most critical): the sources I found seem to indicate that ddr5 always runs at 1.1V (or more but probably not in laptops), while lpddr5 can be downvolted. That's an extra 10% idle power consumption per.

It's true for any laptops that can be reasonably described as having a "SoC" and not CPU, anyway.

(I guess you could be extremely pedantic and try to argue that T2 counted as SoC? But clearly not what I meant.)

God forbid someone steps on it too, I think I might still have some scars on my feet.

They are going to lose money when people buy new RAM, rather than a whole new laptop. While processor speeds and size haven't plateaued yet, it's going to take a while to develop significant new speed upgrades and in the meantime, the only other upgrade is disk size/long-term storage, which, aside from Apple, they don't totally control.

So, why should they relenquish that to the user?

It makes sense that the first ones to use this new standard would be Dell and Lenovo. They both have "business" lines of computers, which usually offer on-site repairs (they send the parts and a technician to your office) for a somewhat long time (often 3 or 5 years). To them, it's a cost advantage to make these computers easier to repair. Having the memory (which is a part which not rarely fails) in a separate module means they don't have to replace and refurbish the whole logic board, and having it easy to remove and replace means less time used by the on-site technician (replacing the main logic board or the chassis often means dismantling nearly everything until it can be removed).

Alternatively, it allows them to use more efficient RAM in computer lines they can't make non-repairable so they can boast of higher battery life.

You're thinking about this the wrong way around.

Suppose the user has $800 to buy a new laptop. That's enough to get one with a faster processor than they have right now or more memory, but not both. If they buy one and it's not upgradable, that's not worth it. Wait another year, save up another $200, then buy the one that has both.

Whereas if it can be upgraded, you buy the new one with the faster CPU right away and upgrade the memory in a year. Manufacturer gets your money now instead of later, meanwhile the manufacturer who didn't offer this not only doesn't sell to you in a year, they just lost your business to the competition.

They are going to buy the 800$, any of the two, complain when it inevitably "works slower" in a couple of years (if they are lucky), and buy a new 800$ once again then. I don't see the manufacturer's motivation to offer upgradable RAM.

- the manufacturer themselves benefit from easier to repair machines. If DELL can replace the RAM and send back the laptop in a matter of minutes instead of replacing the whole motherboard to then have it salvaged somewhere else, it's a clear win.

- prosumers will be willing to invest more in a laptop that has better chance to survive a few years. Right now we're all expecting to have parts fail within 2 to 3 years on the higher end, and budget accordingly. You need a serious reason to buy a 3000$/€ laptop that might be dead in 2 years. Knowing it could weather RAM failure without manufacturer repair is a plus.

So it's the egg and the chicken where if it'll be important to consumers, it might end up as catching up.

I love the disclosure at the bottom:

Full Disclosure: iFixit has prior business relationships with both Micron and Lenovo, and we are hopelessly biased in favor of repairable products.

FYI, the '2' at the end is because this isn't the first time this has been done. :)

LPCAMM spec has been out for a while. LPCAMM2 is the spec for next-generation parts.

Don't expect either to become mainstream. It's relatively more expensive and space-consuming to build an LPCAMM motherboard versus dropping the RAM chips directly on to the motherboard.

I kind of wish we could establish a new level in the memory hierarchy. Like, just make a slot where you can add slower more power hungry DDR RAM that acts as a big cache for the NVM storage, or that the OS can offload some of the stuff in main memory if it's not used much. It could be unpopulated in base models, and then you can buy an upgrade to stick in there to get some extra performance later if needed.

Too bad apple is almost guaranteed to not adopt the standard. I miss being able to upgrade the ram in macbooks.

Apple would require multiple LPCAMM2 modules to provide the bus width necessary for their chips. Up to 4 x LPCAMM2 modules depending on the processor.

The size of each LPCAMM2 module is almost as big as the entire size of an Apple CPU combined with the unified RAM chips, so putting 2-4 LPCAMM2 modules on the board is completely infeasible without significantly increasing the size of the laptop.

Remember, the Apple architecture is a combined CPU/GPU architecture and has memory bandwidth to match. It's closer to your GPU than the CPU in your non-Mac machine. Asking to have upgradeable RAM on Apple laptops is akin to almost like asking for upgradeable RAM on your GPU (which would not be cheap or easy)

For every 1 person who thinks they'd want a bigger MacBook Pro if it enabled memory upgrades, there are many, many more people who would gladly take the smaller size of the integrated solution we have today.

The non-Pro/Max versions (e.g. M3) uses 128-bits, and arguably is the kind of notebook that mostly needs to be upgraded later since they commonly come with only 8GB of RAM.

Even the Pro versions (e.g. M3 Pro) use up-to 256-bits, that would be 2 x LPCAMM2 modules, that seem plausible.

For the M3 Max in the Macbook Pro, yes, 4 x LPCAMM2 would be impossible (probably). But I think you could have something like the Mac Studio have them, that is arguably also the kind of device that you probably want to increase memory in the future.

Is it feasible to fit memory bandwidth like the M3 Max (512 bits wide LPDDR5-6400) with LPCAMM2 in a thin/light laptop?

Most macbooks dont need high memory bandwidth, most users are using their macs for word processing, excel and vscode.

I expanded it to 32 GB RAM, 3 TB SSD but it's still a i7 4xxx with 1666 MHz RAM. And yet it's OK for Ruby, Python, Node, PostgreSQL, docker. I don't feel the need to upgrade. I will when I'll get a major failure and no spare parts to fix it.

So yes, low end Macs are probably good for nearly everything.

Good for your niche case, the other 99.8% still only does web and low performance desktop applications (which includes IDEs)

They instead position midrange products from 1-2 gens ago as their entry level which isn’t quite as cheap but is usually also much more pleasant to use than the usual bargain basement stuff.

Heck, make it only run full tilt when on an active cooling dock. Let it run half power when unassisted.

Also a gaming laptop is handy if you want to travel and game at your hotel.

A machine like that could still be relatively small but still be dramatically better cooled than even the thickest laptop due to not having to make space for a battery, keyboard, etc.

Also replacing them is not rocket science. I reckon I could do one fine (used to do rework). The software side is the bugbear.

Why can't the signaling channels use a higher voltage and control circuitry on the memory stick step up and step down the gain to access the memory module?

RAM is nice to upgrade, for sure. As well as an SSD, but CPUs are still a must. I would even suggest upgradeable GPUs but I don't think the money is there for the manufacturers. Why allow you to upgrade when you can buy a whole new laptop?

RAM/Storage are great upgrades because 5 years from now you can pop in 4x the capacity at a bargain since it's the "old slow type". CPUs don't really get the same growth in a socket's lifespan.

The RAM/SSD sure - a 2 TB consumer SSD wasn't even a possible thing to buy until a year after that laptop would have come out and you can get that for <$100 new now. It won't be the highest performing modern drive but it'll still max out the bus and be many times larger than the original drive. Swap equipment 3 years from now and that's also still a great usable drive rather than a museum piece. Upgrading to a CPU that you could have gotten around the time the laptop came out? Sure, it has twice as many cores... but it still has pretty bad multi core performance and a god awful perf/wattage ratio to be investing new money on a laptop for. It's also a bit of a dead end, in 3 years you'll now have 2 CPUs so ancient you can't really do much with them.

  - Every time a new ToTL GPU comes out for a new family, buy it at retail price as soon as it launches (so, the first-available ToTL models that were big gains in perf: GTX 1080 Ti, RTX 2080 Ti, RTX 3090, RTX 4090)

  - Every other release cycle, upgrade CPU to the ToTL consumer chip (eg on a 12900KS right now, HEDT like ThreadRipper is super expensive and not usually better for gaming or normal dev stuff). I was with Ryzen since 1800x -> 3950x -> 5950x but Intel is better for the particular game I play 90% of the time.

  - Every time you upgrade, sell the stuff you've upgraded ASAP. If you do this right and never pay above MSRP for parts, you can usually keep running very high-end hardware for minimal TCO.

  - Buy a great case, ToTL >1000w PSU (Seasonic or be quiet!), and ToTL cooling system (currently on half a dozen 140mm Noctua fans and a Corsair 420mm AIO). This should last at least 3 generations of upgrading the other stuff.

  - Storage moves more slowly than the rest, and I've had cycles where I've re-used RAM as well, so again here go for the good stuff to maximize perf, but older SSDs work great for home servers or whatever else.

  - Monitor and other peripherals are outside of the scope of this but should hopefully last at least 3 upgrade generations. I bit when OLED TVs supported 4K 120hz G-Sync, so I've got a 55" LG G1 that I'm still quite happy with and not wanting to immediately upgrade, though I do wish they made it in a 42" size, and 16:10 would be just perfect.

The technical differences between sockets aren't usually huge. Upgrade the memory standard here, add or remove PCIe lanes there. Using new cores with an older memory controller may or may not be doable, but it's quite simple to not connect all the PCIe lanes the die supports.

Because you can't swap the motherboard, your options for CPUs are going to be quite limited. Generally, only higher-tier CPUs of that same generation - which draw more power and require more cooling.

Generally a laptop is built designed to provide a specific budget of power to the CPU and has a limited amount of cooling.

Even if you could swap out the CPU, it wouldn't work properly if the laptop couldn't provide the necessary power or cooling.

And the good thing about mobile CPUs is that they have almost the same TDP across the various dual-quad versions(or whatever is the norm today).

IMO the switch to an SSD would have been the biggest boost.

In a way I don't mind having non-replaceable ram in the framework ecosystem as an option. Put simply because the motherboard itself is modular and needs to be upgraded for the CPU. At that point though I would prefer on integrated ram CPU/GPU.

If we can convince the companies to actually try for compatibility, then a revival of MXM is probably a significantly better option.

In framework's case, the cooling is integrated in the gpu module, and both it's size, cooling and power deliver can be adjusted depending on the gpu power.

A friend of mine was betrayed on this by MSI, where laptops with GTX 900 series GPUs were promised upgrades and then when the 1000 series came out they didn't offer any. I think they did make weak excuses about power use, but a 1060 would have fit within the power budget fine and been an enormous upgrade. A few people have even gotten 1060 modules to work with BIOS edits, so it wasn't some other incompatibility. It seems like they saw they couldn't offer a 1080 and threw out the entire project and promise, and then offered a mild discount on a brand new laptop, no other recourse.

This way, you could keep power consumption low and be able to upgrade cpu to a new generation

And soldering stuff to the board is the default way to make something when upgradeability isn't a feature.

EDIT: article about a tech demo of it on a laptop actually, hadn't seen this before: https://www.techradar.com/pro/even-a-laptop-can-run-ram-exte...

This[1] Anandtech article from last year has a better look at how the LPCAMM module works. Especially note how the connectors are now densely packed directly under the memory chips, significantly reducing the trace length needed. Not just on the memory module itself but also on the motherboard due to the more compact memory module. It also allows for more pins to be connected, thus higher bandwidth (more bits per cycle).

[1]: https://www.anandtech.com/show/21069/modular-lpddr-becomes-a...

While certainly not the largest losses, they do not appear insignificant. In LPDDDR4 they introduced[1] a new low-voltage signalling, which I doubt they could have gotten working with SODIMMs due to the extra parasitics.

If you look at this[2] presentation you can see that at 3200MHz a DDR4 SODIMM would consume around 2 x 16 x 4 x 6.5mW x 3.2GHz = 2.6W for signalling going full tilt. Thanks to the new signalling LPDDR4 reduces this by 40% to around 1.6W.

Compare that to a low-power CPU having a TDP of 10W or less a full 1W reduction per SODIMM just due to signalling isn't insignificant.

To further put it into perspective, the recent Lenovo ThinkPad X1[3] uses around 4.15W average during normal usage, and that includes the screen.

Obviously the memory isn't going full tilt at normal load, but say average 0.25W x 2 sticks would reduce the X1's battery lifetime by 10%.

edit: yes I'm aware the presentation is about LPDDR4 yet the X1 uses LPDDR5, just trying add context using available sources.

[1]: https://www.jedec.org/news/pressreleases/jedec-releases-lpdd...

[2]: https://www.jedec.org/sites/default/files/JY_Choi_Mobile_For...

[3]: https://www.tomshardware.com/reviews/lenovo-thinkpad-x1-carb...

Yet another standard for memory will just fail.

And you'd be able to have a lot more than 192GB.

Unless “impossibly far profit margin” is a technical requirement.

There is, Apple uses flash memory as swap to get away with low RAM specs, and the latency and speed required for that purpose all but necessitates putting the flash memory directly next to the SoC.

I do hope that a more widespread usage of compressed attachment gives us some development in that area where projects that were promising modular devices failed (remember those 'modular' phone concepts? available physical interconnects were one of the failures...). Sockets for BGAs have existed for a while, but were not really end-user friendly (not that LGA or PGA are that amazing), so maybe my hope is misplaced and many-contact connections will always be worse than direct attachment (be it PCB or SiP/SoC/CPU shared substrate).

As much as I like socketed / user-replaceable parts, fact is that soldering down a BGA is a very reliable way to make those many connections.

On devices like smartphones & tablets RAM would hardly ever be upgraded even if possible. On laptops most users don't bother. On Raspberry Pi style SBCs it's not doable.

Desktops, workstations & servers are the exception here.

Basically the high-speed parts of a system need to be as close together as physically possible. Especially if low power consumption is important.

Want easy upgrades? Then compute module + carrier board setups might be the way to go. Keep your I/O connectors / display / SSD etc, swap out the CPU/GPU/RAM part.

until you hit custom undocumented unobtainium proprietary chips. good luck repairing anything with those.

There's lots of value in tight integration. Improved signal integrity (ie, faster), improved reliability, better thermal flow, smaller packaging, and lower cost. Do I really want to compromise all of those things just to make RAM upgrades easier?

And how many times do I need to upgrade the RAM in a laptop, really? Twice? Why make all those sacrifices to use a connector, instead of just reworking the DRAM parts? A robotic reflow machine is not so complex that a small repair shop couldn't afford one, which is what you see if you to to parts of the world where repair is taken seriously. Why do I need to be able to do it at home? I can't re-machine my engine at home. It's the most advanced nanotechnology humanity can produce, why is a $5k repair setup unreasonable?

This is not to mention the direction things are really going, DRAM on Package/Die. The signaling speed and bus widths possible with co-packaged memory and HBM are impossible to avoid, and I'm not going to complain about the fact that I can't upgrade the RAM separately from the CPU, any more than I complain about not being able to upgrade my L2 cache today. The memory is part of the compute, in the same way the GPU memory is part of the GPU.

I hope players like iFixit and Framework aren't too stubborn in opposing the tight integration of modern platforms. "Repairable" doesn't need to mean the same thing it did 10 years ago, and there are so many repairability battles that are actually worth fighting, that being stubborn about the SOTA isn't productive.

Don't know would say the reverse, workstation might need the performance of DRAM on Package/Die, but I don't believe it's the case for mainstream user.

> A robotic reflow machine

Same maybe to service enterprise customer but probably way too expensive for mainstream.

I certainly hope that players continue to oppose tight integration and I'll try to support them. I value the ability that anyone can swap ram and disks to easily upgrade or repair their device more than an increase of performance or even battery life.

I recently cobbled up a computer for a friend's child with component from three different computers; any additional cost would have made the exercise worthless.