Yes.

Actually, it’s everything: en.wikipedia.org/wiki/Random-access_memory#Memory…

…But also, your friend is wrong. And its complicated.

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First some background. There are a couple of “regular” types of RAM basically every product uses under the hood. And every one is a set of tradeoffs: bandwidth, latency, capacity, power efficiency, trace lengths, expense, and so on. A few of types:

• “Regular” DDR. This is what you see on sticks for desktops, laptops, and servers.

• LPDDR. Its power-optimized at the expense of some latency and trace length, but its specs are otherwise similar to DDR. This is what smartphones (and Macs) use.

• GDDR. Optimized for bandwidth and cost over everything. Guzzles power. Used on gaming GPUs.

• HBM. Low speed, requires extremely short trace lengths, but low power and latency. Uses an exotic bus with exotic manufacturing techniques. This is what you see on more exotic server accelerators.

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But the packaging is also really, really important too. For example, regular DDR5 can come in:

• Unregistered RAM sticks, for your desktop.

• As registered RAM, for servers.

• As SODIMM, for laptops.

And these all have long traces, since they have to come in sticks. They’re “far” from the CPU. Laptop SODIMMS, in particular, have a really poor path to the CPU, and start to run into huge scaling issues at DDR5 speed.

…In other words, laptop DDR5 SODIMMS are particularly slow, because the socket they sit in simply cannot keep up with their speeds.

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As for LPDDR5: its specification assumes a shorter, higher quality trace or “wire” to the CPU, hence it can only come soldered, and sitting right next to the CPU:

Samsung graphic

But electrically, it’s almost the same as DDR5! It’s not wider-and-slower like HBM, or more tweaked like GDDR5: it’s just regular old cheap DDR5, massaged to work better soldered to the motherboard.

This is what Macs use.

They’re not using “special Apple RAM” like is the popular perception. They’re using smartphone RAM. Its a bit faster becase it is “closer” to the CPU, but this is misleading, as its nothing like more exotic standards that really take advantage of that proximity. If you read this, its much closer to GDDR5 than HBM: graphicscardhub.com/gddr5-vs-gddr5x-vs-hbm-vs-hbm…

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In practice, Apple RAM is faster and “closer” to the CPU, but its more because of business design choices than a particularly exotic memory specification:

• Apple uses very wide buses for their CPUs. Typical laptops are 64-bit or 128-bit, Apple stuff can be 192-bit to 512-bit. This is more expensive, and you pay for it in the sticker price.

• Regular laptops use swappable SODIMM sticks, which have a tremendous speed cost. Apple doesn’t have to worry about this.

• Apple pays a premium for fast, binned LPDDR5, regular OEMs do not.

But it doesn’t have to be this way.

Some laptops already use swappable LPCAMM modules, which for all practical purposes are just as fast as Apple’s RAM, and just as “close to the CPU” from an electrical perspective:

LPCAMM module

Framework was very close to implementing this for AMD’s 256-bit Strix Halo CPUs. They could quite work out the electrical gremlins before release.

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TL;DR

Apple RAM is “closer to the CPU” in the existing market, but there’s no technical reason PCs have to be any different.

Apple uses off-the-shelf smartphone RAM, basically.

An AMD Strix Halo laptop, with 2 LPCAMM modules, would be just as fast as Apple memory, and just as “close” to the CPU. Some PCs already do this on a smaller scale.

So strictly speaking, your friend is correct. But its misleading. All that really matters is the memory specification laptop/desktop manufacturers choose.