LPCAMM2 is a modular, repairable, upgradeable memory standard for laptops

Post by smolder » Tue, May 07, 2024, 9:28 PM UTC

OJFord wrote: post #53

orev wrote: post #14

I’m glad they explained why RAM has become soldered to the board recently. It’s easy to be cynical and assume they were doing it for profit motive purposes (which might be a nice side effect), but it’s good to know that there’s also a technical reason to solder it. Even better to know that it’s been recognized and a solution is being worked on.

I didn't find that a particularly complete explanation - and the slot can't be closer to the CPU because? - I think it must be more about parasitic properties of the card edge connector on DIMMs being problematic at lower voltage (and higher frequencies) or something. Note the solution is a ball grid connection and the whole thing's shielded. I suppose in fairness and to the explanation it does give, the other thing…

Post by kjkjadksj » Tue, May 07, 2024, 9:36 PM UTC

orev wrote: post #14

I’m glad they explained why RAM has become soldered to the board recently. It’s easy to be cynical and assume they were doing it for profit motive purposes (which might be a nice side effect), but it’s good to know that there’s also a technical reason to solder it. Even better to know that it’s been recognized and a solution is being worked on.

Post by kjkjadksj » Tue, May 07, 2024, 9:38 PM UTC

magicalhippo wrote: post #39

dvh wrote: post #6

What's wrong with DIMM?

The physical size of the socket and having the connections on the edge means you're forced to have much longer traces. Longer traces means slower signalling and more power loss due to higher resistance and parasitics. 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 reduci…

Post by 7speter » Tue, May 07, 2024, 9:52 PM UTC

pja wrote: post #22

sliken wrote: post #15

Earlier quoted context omitted.

Apple ships 128 bit, 256 bit, and 512 bit wide memory interfaces on laptops (up to 1024 bit wide on desktops). Is it feasible to fit memory bandwidth like the M3 Max (512 bits wide LPDDR5-6400) with LPCAMM2 in a thin/light laptop?

This PDF[1] suggests that an LPCAMM2 module has a 128 bit wide memory interface, so the epic memory bandwidth of the M3 max won’t be achievable with one of these memory modules. High end devices could potentially have two or more of them arranged around the CPU though? [1] https://investors.micron.com/node/47186/pdf

Post by Rohansi » Tue, May 07, 2024, 10:02 PM UTC

farmdve wrote: post #30

Night_Thastus wrote: post #26

Earlier quoted context omitted.

On a laptop it's not very practical. 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 properl…

I can't say I agree. Back in 2014 a laptop was purchased with a dual-core haswell CPU. 8 years later I revive the laptop by upgrading the CPU to almost the best possible CPU, which is a 4-core 8 thread CPU or 4-core 4 threads, I am unsure which of these it was, but the speed boost was massive. This is how you keep old tech alive. And the good thing about mobile CPUs is that they have almost the same TDP across the va…