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Comment by 2OEH8eoCRo0 | Hacker News Reader

I'm no silicon architect but isn't this why performance is so good? They can cut out all those extra pcie lanes and extraneous stuff and focus on performance. If you start adding back big I/O won't you just be back down to Earth with everyone else?

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Not really. The main reason the M1 doesn't have good IO is that it's a beefed up ipad CPU. This was the first generation where they were putting the chips in systems that can use IO, so they probably are just behind on the design for those parts of the chip.

> The main reason the M1 doesn't have good IO is that it's a beefed up ipad CPU. This was the first generation where they were putting the chips in systems that can use IO

Could you explain what you mean by this? I don't think I understand.

All of Apple’s prior ARM experience comes from iOS devices. They had no need to develop io capabilities for iPhones and iPads with a single port. Now they put the chips in computers but most likely haven’t fully yet developed extended io capabilities.

Hmm, but wouldn't features like wifi, all the cameras, the touchscreen, Cellular data, NFC, touch ID, speakers, bluetooth, and so on all come in via IO as well? You're right that they only have one port, but they still connect to a lot of different components.

Those usually connect over serial-esque busses, and they connect via a security chip. (Akin to the t2 chip but much lighter)

A far cry from the kind of tolerances and sustained high throughput of PCIe.

The problem with this analogy is that NFC, touch ID, speakers, and bluetooth are all in the MB/s or less range. On the desktop side, you have to deal with 10gb/s ethernet and 50-100gb/s for ram. It's just a whole different ballgame.

Ah, that makes sense. Do iPhones connect to their RAM differently? I know it’s physically different than desktop RAM (for obvious reasons), but I don’t really know enough about hardware to know how it connects.

What do you mean the M1 doesn't have good IO?

A 1 Tb Mini with all the SSD write lines benchmarked at

Write: 2,983 MB/Sec Read: 2,710 MB/Sec

That's as fast or faster than Intel Macs, and way higher than most PC SSDs.

Chip I/O as in having lots of memory channels and lots of PCIe lanes.

That said, Intel mobile CPUs don't have fantastic I/O either, this will matter more when Apple has to scale up to iMac Pro/Mac Pro territory.

"SSD performance" is a very high-level view of I/O, and depends more on the size and configuration of flash chips used than the CPU design.

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