[adrian_b]

The value of ARM is that anyone with enough money can license Arm cores and incorporate them in their own products, which can be optimized for some custom applications.

The level of customization possible with an x86 CPU is much less. You must buy a complete computer board or module and incorporate it in your product.

While for custom applications it is easy to create a superior solution with Arm cores, for general-purpose computers it is hard to compete with the Intel and AMD CPUs. All the computers with Arm cores have worse performance per dollar than similar x86 computers. (For instance there was recently a thread on HN about a credit-card-sized computer with an Intel N100 CPU and with the same price or lower as a Raspberry Pi, but with a much higher performance.)

[hypercube33]

AMD does offer custom x86 - see the steam deck, surface laptops and Xbox and PS4 and 5. Given there aren't a ton of small fish making custom parts they are excellent at what they are made for.

AMD is pushing x86 to Apple ARM levels that keep power use low enough (best I've seen is 16 hour battery life on a device - I think MacBooks best this still) but performance per watt I haven't seen ARM really top charts. They are awesome and I want arm and risc-v to really shine in laptops but the only player on the PC side is Qualcomm who was told to destroy their only flagship by ARM.

[soulbadguy]

> AMD does offer custom x86

Not the same thing. On X86 you have to pay AMD or intel to design something for you.

In arm, you get to decide who design your chip or even have your own in house CPU design team.

[Panzer04]

These sorts of processors are available from Intel as well (if anything, more available, as you can buy low-end 5w processors with modern e-cores in them, eg. N95/N97). The commenter above is referring to these, and they are common in Mini-Pcs with 8-16GB of RAM and cost <200USD. These sorts of processors crush the ARM competition at the same level right now (ie. the pi).

In fact, AMD doesn't seem to have anything in the same segment currently, although they do exist in the higher tiers alongside Intel with their laptop processors.

[AlexDragusin]

Radxa X4 low-cost, credit card-sized Intel N100 SBC goes for $60 and up https://news.ycombinator.com/item?id=41007348

[klelatti]

You’ve missed out one of Arm’s central value propositions which is power efficiency and the reason why it has more than 99% of the smartphone market.

[adrian_b]

There have been tons of proprietary CPU architectures with the same power efficiency as Arm. Only the x86 architecture is an outlier that requires an unusually complicated instruction decoder, which may degrade a little the energy efficiency.

Arm has eliminated most of the competing CPU architectures not by providing better power or energy efficiency, but by its business model of being licensable to anyone.

The ARM ISA was somewhat better than MIPS and SPARC, both of which have been handicapped by including some experimental features that have been later proved to be bad ideas. However there have been many other RISC ISAs more or less equivalent with ARM. Only the business model has extracted ARM from the crowd, not its technical advantages.

[klelatti]

You're conflating the characteristics of the ISA with the value proposition offered by the designs using it. Not the same at all.

Other historical architectures typically targeted higher performance.

Arm specifically went after low-power applications, which continues today when we see the priorities in the design of Arm and x86 cores, for example.

[adrian_b]

Arm "specifically went after low-power applications" only in comparison with x86 or in comparison with a few other architectures restricted to workstations and servers, like DEC Alpha or Intel Itanium.

Before 2000, there were at least a dozen CPU architectures that went for the same low-power applications as Arm. There were a lot of microcontroller or processor vendors and each one of them had at least one proprietary ISA, if not 2 or 3 or even more different proprietary ISAs.

More than 20 years ago, I have redesigned various kinds of communication equipment, in order to replace many other kinds of CPUs, for example Motorola MC683xx or ColdFire or IBM PowerPC CPUs, with Arm CPUs.

In none of those cases the Arm CPUs had a lower power consumption or any other technical advantage. In fact in all cases the Arm CPUs were technically inferior to the CPUs replaced by them, which has required the implementation of various hardware and software workarounds.

There was only one reason why the Arm CPUs had been selected to replace their predecessors with different architectures, and that was the lower price. Their lower price was in great part due to the fact that there already were many competing vendors of Arm CPUs, so if you did not like one of them it was easy to replace it with another vendor.

[klelatti]

I get it that you don’t like Arm but that doesn’t change the fact that low power was and is central to their value proposition - and this latter fact doesn’t preclude other firms having low power offerings.

[soulbadguy]

It's been said many time and the correlation between ISA and power efficiency have been debunked many time. ARM is power efficient because most ARM implementation are power efficient. Right now x86 AMD strix are about on par with qualcom x elites

[klelatti]

Agreed. That power efficiency is still a central part of the Arm value proposition though. Others are competing with real designs on this with Arm in laptops but not in - for example - smartphones.