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Now that Apple is switching the MacOS platform to ARM chips, much has been said about the benefits of ARM processors (they save energy, are passively cooled, and the Apple M1 seems to be faster than even an Intel Core i9 processor).

I'd like to know what advantages of the x86 platform are left. Are there any specific circumstances where the x86 CPUs still have the edge? AFAIK they have an much bigger instruction set than the ARM chips. Under what circumstances is the bigger instruction set an advantage, and why?

Note that I'm not asking about a specific software ecosystem like Windows. I know that Windows has many software titles (e.g. games) that don't run (yet) on any ARM platform. That's not the answer I want to hear. An ecosystem advantage like that of Windows is more or less baggage from previous years. It does not necessarily mean that the CPU platform is in any way better, today.

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  • $\begingroup$ The article you linked cites geekbench.com, which seems to be quite inconsistent internally. The top single-core results are much faster than the M1, but the top Mac results don't include those faster systems even though they're Macs. The article was based on the second page. Also, though a Windows version of Geekbench exists, there seem to be relatively few PC benchmarks on the site and there's no PC summary page, so I'm not sure this is really representative of the x86/x64 world in general. $\endgroup$ – benrg Dec 4 '20 at 1:04
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I'll start with the commonly known stuff, that are currently talked about the most.

x86

All x86 processors are developed from the CISC (Complex Instruction Set Computers) architecture. The x86 processors allow you to perform several activities at the same time from a single instruction. Also, they can perform numerous simultaneous tasks without any of them being affected.

This makes them very sophisticated and advanced processors, allowing many complex calculations in a short time. The disadvantage of this design is that they need a lot of power to function and more power means more heat.

Summary: x86 chips are designed to be power hungry and high clocked, multi-thread, high instructions per cycle. In the general use-case they will be a lot faster than your common ARM chip.

ARM

As for ARM processors, they are based on the RISC (Reduced Instruction Set Computer) architecture, which is much simpler than CISC. These processors can do a much smaller number of calculations since they require several commands to act.

RISC instructions are smaller and faster to process, so in part, the disadvantage of having to process several commands for a single action is minimized. Still, ARM processors are much less powerful than the x86.

Summary: ARM chips are designed for low power draw, flexibility, low cost and low heat with good performance.

source of the info above

SoC M1

M1 is not a CPU. It is a whole system of multiple chips put into one large silicon package. The CPU is just one of these chips. And that's the main reason why it's so different and fast compared to the typical ARM chip.

Basically, the M1 is one whole computer onto a chip. The M1 contains a CPU, graphical processing unit (GPU), memory, input and output controllers, and many more things making up a whole computer. This is what is call a system on a chip (SoC).

In the past computers would have multiple physically separate chips on the motherboard of the computer. However because we are able to put so many transistors on a silicon die today, companies such as Intel and AMD began putting multiple microprocessors onto one chip (CPU cores). One core is basically a full independent chip that can read instructions from memory and perform calculations. This has for a long time been the name of the game in terms of increasing performance - just add more general-purpose CPU cores.

Instead of adding ever more general-purpose CPU cores, Apple has followed another strategy - they have started adding ever more specialized chips doing a few specialized tasks. The benefit of this is that specialized chips tend to be able to perform their tasks significantly faster using much less electric current than a general-purpose CPU core.

Hope that answers your question.

You can find more details on the M1 where I got the info for the second part of the answer. There is a lot of additional and interesting info on the CPU market and the software differences inside the M1 and Intel/AMD chips: link

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