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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

by sliken 2y ago

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?

pja 2y ago
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 https://investors.micron.com/node/47186/pdf
- 7speter 2y ago
  Apple could just make lower tier macbooks but mac fanboys wouldnt be able to ask “but what about apples quarterly profits?” Most macbooks dont need high memory bandwidth, most users are using their macs for word processing, excel and vscode.
  - teaearlgraycold 2y ago
    Yes but Apple’s trying to build an ecosystem where users get highly quality, offline, low latency AI computed on their device. Today there’s not much of that. And I don’t think they even really know what’s going to justify all of that silicon in the neural engine and the memory bandwidth. Imagine 5 years from now people have built whole stacks on that foundation. And then competing laptops need to ship that compute to the cloud, with all of the unsolvable problems that come with that. Privacy, service costs (ads?), latency, reliability.
    - jwells89 2y ago
      Apple is also deliberately avoiding having “celeron” type products in their lineup because those ultimately mar the brand’s image due to being kinda crap, even if they’re technically adequate for the tasks they’re used for. 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.
      - deleted 2y ago
        [deleted]
  - sliken 2y ago
    Even low end gaming, simulations, and even fun webGL toys can require a fair amount of memory bandwidth with an iGPU, like apple's M series. It also helps quite a bit for inference. I MBP with a M3 max can run models requiring multiple GPUs on a desktop and still get decent perf for single users.
    - consp 2y ago
      > I MBP with a M3 max can run models requiring multiple GPUs on a desktop and still get decent perf for single users. Good for your niche case, the other 99.8% still only does web and low performance desktop applications (which includes IDEs)
  - pmontra 2y ago
    As a non Mac reference, I work on a HP laptop from 2014. It was a high end laptop by then. It's between 300 and 600 Euro refurbished now. 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.
wmf 2y ago
For 512 bits you would need four LPCAMM2s. I could imagine putting two on opposite sides of the SoC but four might require a huge motherboard.
- kristianp 2y ago
  Perhaps future LPCAMM generations will require more bits? I still can't imagine apple using them unless required by right to repair laws. But those laws probably don't extend to making RAM upgradeable.
jauntywundrkind 2y ago
Hoping we see AMD Strix Halo with it's 256-bit interface crammed into an aggressively cooled fairly-thin fairly-light. But it's going to require heavy cooling to make full use of. Heck, make it only run full tilt when on an active cooling dock. Let it run half power when unassisted.
- seanp2k2 2y ago
  Kinda hilarious to see gamers buying laptops that can't actually leave the house in any practical meaningful way. I feel like some of them would be better off with SFF PCs and the external monitors they already use. I guess the biggest appeal I've seen is the ability to fold up the gaming laptop and put the dock away to get it off the desk, but then moving to an SFF on the ground plus a wireless gaming keyboard and wireless mouse that they already use with the normal laptop + one of those compact "portable" monitors seems like it'd solve the same problem.
  - kristianp 2y ago
    My wife can get an hour of gaming out of her gaming laptop. They're good for being able to game in an area of the house where the rest of the family is, even if that means being plugged in at the dining table. Our home office isn't close enough. Also a gaming laptop is handy if you want to travel and game at your hotel.
  - jwells89 2y ago
    I’ve been wondering for a while now why ASUS or some other gaming laptop manufacturer doesn’t take one of their flagship gaming laptop motherboards, put some beefy but quiet cooling on it, put it in a pizza-box/console enclosure, and sell it as a silent compact gaming desktop. 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.
    - antonkochubey 2y ago
      ZOTAC does these - there are ZBOX Magnus with laptop-grade RTX 4000 series GPUs in 2-3 liter chassis. However their performance and acoustics are rather.. compromised, compared to a proper SFF desktop (which can be built in ~3x the volume)
AnthonyMouse 2y ago
Apple does this because their CPU and GPU use the same memory, and it's generally the GPU that benefits from more memory bandwidth. Whereas in a PC optimized for GPU work you'd have a discrete GPU that has its own memory which is even faster than that.

by sliken 2y ago

pja 2y ago

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 https://investors.micron.com/node/47186/pdf

7speter 2y ago
Apple could just make lower tier macbooks but mac fanboys wouldnt be able to ask “but what about apples quarterly profits?” Most macbooks dont need high memory bandwidth, most users are using their macs for word processing, excel and vscode.
- teaearlgraycold 2y ago
  Yes but Apple’s trying to build an ecosystem where users get highly quality, offline, low latency AI computed on their device. Today there’s not much of that. And I don’t think they even really know what’s going to justify all of that silicon in the neural engine and the memory bandwidth. Imagine 5 years from now people have built whole stacks on that foundation. And then competing laptops need to ship that compute to the cloud, with all of the unsolvable problems that come with that. Privacy, service costs (ads?), latency, reliability.
  - jwells89 2y ago
    Apple is also deliberately avoiding having “celeron” type products in their lineup because those ultimately mar the brand’s image due to being kinda crap, even if they’re technically adequate for the tasks they’re used for. 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.
    - deleted 2y ago
      [deleted]
- sliken 2y ago
  Even low end gaming, simulations, and even fun webGL toys can require a fair amount of memory bandwidth with an iGPU, like apple's M series. It also helps quite a bit for inference. I MBP with a M3 max can run models requiring multiple GPUs on a desktop and still get decent perf for single users.
  - consp 2y ago
    > I MBP with a M3 max can run models requiring multiple GPUs on a desktop and still get decent perf for single users. Good for your niche case, the other 99.8% still only does web and low performance desktop applications (which includes IDEs)
- pmontra 2y ago
  As a non Mac reference, I work on a HP laptop from 2014. It was a high end laptop by then. It's between 300 and 600 Euro refurbished now. 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.

wmf 2y ago

For 512 bits you would need four LPCAMM2s. I could imagine putting two on opposite sides of the SoC but four might require a huge motherboard.

kristianp 2y ago
Perhaps future LPCAMM generations will require more bits? I still can't imagine apple using them unless required by right to repair laws. But those laws probably don't extend to making RAM upgradeable.

jauntywundrkind 2y ago

Hoping we see AMD Strix Halo with it's 256-bit interface crammed into an aggressively cooled fairly-thin fairly-light. But it's going to require heavy cooling to make full use of. Heck, make it only run full tilt when on an active cooling dock. Let it run half power when unassisted.

seanp2k2 2y ago
Kinda hilarious to see gamers buying laptops that can't actually leave the house in any practical meaningful way. I feel like some of them would be better off with SFF PCs and the external monitors they already use. I guess the biggest appeal I've seen is the ability to fold up the gaming laptop and put the dock away to get it off the desk, but then moving to an SFF on the ground plus a wireless gaming keyboard and wireless mouse that they already use with the normal laptop + one of those compact "portable" monitors seems like it'd solve the same problem.
- kristianp 2y ago
  My wife can get an hour of gaming out of her gaming laptop. They're good for being able to game in an area of the house where the rest of the family is, even if that means being plugged in at the dining table. Our home office isn't close enough. Also a gaming laptop is handy if you want to travel and game at your hotel.
- jwells89 2y ago
  I’ve been wondering for a while now why ASUS or some other gaming laptop manufacturer doesn’t take one of their flagship gaming laptop motherboards, put some beefy but quiet cooling on it, put it in a pizza-box/console enclosure, and sell it as a silent compact gaming desktop. 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.
  - antonkochubey 2y ago
    ZOTAC does these - there are ZBOX Magnus with laptop-grade RTX 4000 series GPUs in 2-3 liter chassis. However their performance and acoustics are rather.. compromised, compared to a proper SFF desktop (which can be built in ~3x the volume)

AnthonyMouse 2y ago

Apple does this because their CPU and GPU use the same memory, and it's generally the GPU that benefits from more memory bandwidth. Whereas in a PC optimized for GPU work you'd have a discrete GPU that has its own memory which is even faster than that.