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Comment by exabrial | Hacker News Reader

I can't believe how much we've been focused on core speed when memory bandwidth and latency has been such a huge issue... at least for my workloads. My stuff screams on a M1 Chip.

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AMD and Intel have the same 128-bit LPDDR5-6400 as the M2.

Do point me to an x86 laptop I can buy with 100GB/s of memory bandwidth to the CPU.

What exactly are you asking for here? Because you've already been informed that AMD and Intel systems using LPDDR5 at the same speed and bus width are now available. On paper, every new laptop using soldered LPDDR is now over 100GB/s for DRAM bandwidth. Are you asking for synthetic benchmark results comparing achievable throughput against theoretical bandwidth, or are you just being obtuse?

I am asking for a name of one that has been demonstrated to actually do that. Not promise. Not “on paper”. Actually do. Extra credit if it actually exists in a store to actually buy. Today.

Such information is no longer available due to the demise of tech journalism.

And yet somehow you are sure such things exist?

Look, you're probably right but there's no need to be so annoying about it.

Stop confidently making nonsensical claims, like this, then: https://news.ycombinator.com/item?id=35855612

There's nothing nonsensical about the claim that there are AMD and Intel systems using 128-bit LPDDR5-6400. AMD's mobile processors started supporting that config last year, so in spite of this year's mobile processors being a bit late the market is already full of systems so equipped. Intel's mobile processors as of earlier this year also support this memory configuration and speed, and systems have been shipping from multiple vendors for well over a month; they're not exotic or hard to find. There's even at least one announced but not yet shipping Intel-based system that will use LPDDR5-7500!

It's called "overfitting specs". They ask for a very specific set of specs that only Apple laptops have and ignore anything else. If you can find anything that competes they'll move the goalposts and complain about touchpad or something else.

Sorry, still not clear exactly where your goalposts are. Is there a public benchmark where M2 scores above 100GB/s that you'd like to see comparable runs for a recent x86 mobile platform?

Not sure about the M2, but here's one for the M1 Pro/Max: https://www.anandtech.com/show/17024/apple-m1-max-performanc...

For whatever reason, it isn't so easy to find real-world memory bandwidth results for consumer stuff; it's a fairly standard benchmark for server hardware, but less so for consumer. Here's one for an old Ryzen 9: https://www.anandtech.com/show/14605/the-and-ryzen-3700x-390..., but couldn't find anything current offhand.

What kind of work are you doing to need that on a laptop of all things? The usage cases I am aware of are all better suited by non-portable computers dedicated to the task.

That sounds incredibly specialized and I am needlessly curious.

local LLMs

Memory bandwidth (not latency) on mobile SoC is for GPU. It's not very beneficial to have full 100GB/s bus for CPU.

Doesn't M1 and M2 have on-chip memory? Even if it may be the same interface, doesn't the physical distance help make it significantly more performant?

Nope, the shorter distance makes no measurable performance difference. It does make the motherboard smaller though.

I prefer option to upgrade RAM capacity over too high memory bandwidth

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