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Comment by sliken | Hacker News Reader

Well the perception was that AMD and Intel had a unassailable lead. That even with a power and clock speed disadvantage that the M1 can be quite competitive with several other serious mobile chips, like the Intel I9.

Now apple has proved that a cool running chip that sips power can run a wide variety of intensive applications well.

People were quite dubious of apple's chances on a competitive desktop chip and have just received a wake up call with a relatively conservative M1 chip (3.2 GHz and 4 fast cores).

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It wasn't generally thought that amd/intel were unassailable engineering wise, just that sw compatibility, x86 patents and volumes were important enough that it was economically hard to go against them. But other chips (eg IBM) regularly challenged them on speed despite relatively tiny volumes and budgets. And of course years earlier the Itanium debacle + exponentially increasing fab costs (favouring volumes) killed off most of the RISC competition.

Trivia: Simultaneously to the previous Mac ISA transition, Apple acquired PA Semi who had a power efficient and fast PPC chip. Then, Apple decided to go to Intel anyway instead of betting on their new in-house chip. Discarding their newly acquired highly acclaimed chip design, they put the newly acquired semi team to work on the A series of chips instead.

But they had no reason to be skeptical, given the A series. To only take a processor seriously once it’s housed in a case with a keyboard attached is ridiculous.

Well, I kind of agreed with them. It's easy to assume that phone apps written for a few GB ram would not be representative of high end use like compiling large projects, editing 4k video, manipulating large datasets, etc.

But as it turns out the M1 does quite well at quite a few real world aggressive desktop applications.

I was on the other side: Bits are bits, loops are loops. Why there’s a distinction between phone app and desktop app? Isn’t it that the difference is only the UI input method?

At least for the last 5 years an iPhone and a desktop would handle the exact same images, videos, spreadsheets and websites with any desktop and often with better performance. Why would anyone think that these are fundamentally different?

Iphones are generally media consumption devices. Sure they can take pictures and video, but most often they are processed on laptops or desktops.

Similarly programming, compiling, making videos, making music, etc is most often done on laptops and desktops.

Certainly you are right, the M1 is a very capable CPU for all of these things, just that it was a surprise for many.

RAM latency for one thing. Phones have a huge advantage in that area which translates very well to most tasks as long as they have enough memory. OS differences also favor phones in many ways.

No, they don't. Memory latencies for top-end phones like the iPhone are generally over 100 ns, which far from being a huge advantage is consderably worse than the best desktop and latpop x86 chip latencies which hover around 50 ns.

I generally try to quantify TLB latency and DRAM latency separately. The M1 chip has quite impressive memory latency around 30ns, assuming you aren't thrashing the TLB.

Desktops tend to be much higher latency, like say the AMD ryzen 5950X. In particular the R per RV range benchmark uses between 1 and 32 pages in a sliding window. The M1 gets around 30ns (which I've personally verified with code I wrote) and the Ryzen 5950x gets around 65ns. Intel does a bit better than AMD, but nowhere close to the M1.

You’re numbers are way off, where did you get them?

Ex: https://en.wikipedia.org/wiki/CAS_latency

Benchmarks. CAS latency is only a small part of total memory latency as seen by the CPU.

As we are talking about comparing different CPU architectures it’s the external latency that’s important. Even then I have been looking at sub 25ns on AMD CPU memory benchmarks and I assume similar Intel numbers.

If anything it's made me more interested in micro-PC's. I have been playing a lot with Raspberry Pi's lately, and the M1 shows how much better we could do in that form factor. Why can't I have an Apple Silicon SOC the size of an iPhone, with the battery and screen replaced with a heat sync and a couple of ports?

We do and it's called the mac mini. The actual circuit board looks to be about 2x the size of the pi. Their only reason for the massive mini case is economies of scale. They have to leave that case around for the intel mini for another year or two and all the tooling exists, so they didn't have any costs there either.

I think the real next-gen mini should have been the iPhone 12 pro. Imagine a desk with just an Apple monitor, charger, and wireless keyboard. Pop your mag-safe phone onto the charger so you have a trackpad. The mm-wave connects to the monitor for video and giving access to it's USB-c ports. You get the normal mac desktop ready to start working for the day. It's not as powerful as most desktops, but it can give tons of plugged-in laptops a run for their money. More than good enough for 95% of users.

You also have to leave some room for ports.

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