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Arm's Cortex X925: Reaching Desktop Performance

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Re: Arm's Cortex X925: Reaching Desktop Performance

#101

Post by aseipp »

rayiner wrote: post #80

ARM designs are effectively paper launches. You get these press releases saying the new ARM matches Apple and AMD, but its years before you can buy a product with it. Google Pixels that came out in the fall are still on the X4, which was introduced in 2023. At this rate, Pixel 11 will launch with X925, which is an Apple A17/M3 tier core, when Apple is on the A20: https://wccftech.com/apple-a20-and-a20-pro-all-technol…

I feel like that was much more true in the past but the X925 was only spec'd 18 months ago(?) and you can buy it today (I'm using one since October). Intel and AMD also give lots of advance notice on new designs well ahead of anything you can buy. ARM is also moving towards providing completely integrated solutions, so customers like Samsung don't have to take only CPU core and fill in the blanks themselves. They'll probably only get better at shipping complete solutions faster.

Honestly, Apple is the strange one because they never discuss CPUs until they are available to buy in a product; they don't need to bother.

Re: Arm's Cortex X925: Reaching Desktop Performance

#102

Post by __alexs »

pdpi wrote: post #14
ezst wrote: post #10

Earlier quoted context omitted.

That would only matter (to me, at least) if those Apple chips were propping up an open platform that suits my needs. As things stand today, procuring an M chip represents a commitment to the Apple software ecosystem, which Apple made abundantly clear doesn't optimize for user needs. Those marginally faster CPU cycles happen on a time scale that anyway can't offset the wasted time fighting MacOS and re-building decade…

Sure. Insofar as Apple Silicon beats these things, "I'll take less powerful hardware if it means I'm not stuck with the Apple ecosystem" is a perfectly reasonable tradeoff to make. Two things, though. First, I don't like making blind tradeoffs. If what I need (for whatever reason) is a really beefy ARM CPU, I'd like to know what the "Apple-less tax" costs me (if anything!) Second, the status quo is that Apple Silicon…

> the status quo is that Apple Silicon is the undisputed king of ARM CPU performance

If your metric is single thread performance yes but on just about anything else Graviton 4 wins.

Re: Arm's Cortex X925: Reaching Desktop Performance

#103

Post by truelinux1 »

ezst wrote: post #10
pdpi wrote: post #2

Kind of weird to see an article about high-performance ARM cores without a single reference to Apple or how this hardware compares to M4 or M5 cores.

That would only matter (to me, at least) if those Apple chips were propping up an open platform that suits my needs. As things stand today, procuring an M chip represents a commitment to the Apple software ecosystem, which Apple made abundantly clear doesn't optimize for user needs. Those marginally faster CPU cycles happen on a time scale that anyway can't offset the wasted time fighting MacOS and re-building decade…

This echoed my thoughts exactly - Linux only.

Re: Arm's Cortex X925: Reaching Desktop Performance

#104

Post by amluto »

bluGill wrote: post #45
pdpi wrote: post #14

Earlier quoted context omitted.

Sure. Insofar as Apple Silicon beats these things, "I'll take less powerful hardware if it means I'm not stuck with the Apple ecosystem" is a perfectly reasonable tradeoff to make. Two things, though. First, I don't like making blind tradeoffs. If what I need (for whatever reason) is a really beefy ARM CPU, I'd like to know what the "Apple-less tax" costs me (if anything!) Second, the status quo is that Apple Silicon…

Why do you need ARM? There is nothing magic, most CPUs are an internal instruction set with a decoder on top. bad as x86 is, decoding is not the issue. they can make lower power use x86 if they want. They can also make mips or riskv chips that are good.

Sometimes the ISA matters. For example, modern ARM has flexible and lightweight atomics, whereas x86 is almost entirely missing non-totally-ordered RMW operations.

Re: Arm's Cortex X925: Reaching Desktop Performance

#105

Post by lproven »

BlobberSnobber wrote: post #58
ezst wrote: post #38

Earlier quoted context omitted.

Pretty simply because I don't want to use MacOS, its terrible window management, quirks and idiosyncrasies. In your comparison, my gripe wouldn't be about the hassle of finding 3rd-party compatible batteries, but about the daily handling of the Makita while knowing the DeWalt to be more ergonomic and better suited to my needs.

As someone who uses Linux, macOS and Windows interchangeably, I'm curious to know what you're using. I learned to live with macOS, but I also like and use Gnome, which many Linux-only people hate. I tried most WMs on Linux, like Hyprland, Sway, i3, but none ever felt worth the config hassle when compared to the sane defaults of Gnome.

> the sane defaults of Gnome.

I have to admit that when I read this, my eyebrows went up so far that my hat moved.

Re: Arm's Cortex X925: Reaching Desktop Performance

#106

Post by lproven »

mrweasel wrote: post #39
runeks wrote: post #11

Earlier quoted context omitted.

Wouldn't the compiler take care of producing the correct machine code?

OpenBSD famously keeps a lot of esoteric platforms around, because running the same code on multiple architectures reveal a lot of bugs. At least that was one of the arguments previously.

Which is why Windows NT was multiplatform in 1993.

Developed on Intel i860, then MIPS, and only then on x86, alongside Alpha.

Re: Arm's Cortex X925: Reaching Desktop Performance

#107

Post by Symmetry »

hylaride wrote: post #60
DeathArrow wrote: post #30

Earlier quoted context omitted.

This is kind of a solution in search for a problem. RISC-V will grow only if people find some value in it. If it solves their actual problems in ways that other architectures can't.

Yeah, the primary reason RISC-V exists is political (the desire to have an "open source" CPU architecture). As noble as that may be, it's not enough to get people or companies to use (or even manufacture!) it. It'll either be economical (costs) and/or performance (including efficiency) that drives people. It took ARM decades to get to where it is, and that involved a long stint in low-margin niche applications like e…

That might be true for the desktop, but RISC-V is wonderful from a pedagogical and research standpoint for academic uses and in the embedded world its license and "only pay for what you need" is also quite nice.

Re: Arm's Cortex X925: Reaching Desktop Performance

#108

Post by joha4270 »

adgjlsfhk1 wrote: post #94
joha4270 wrote: post #89

Earlier quoted context omitted.

I'm sorry, I'm clearly missing something but why would page size impact L1 cache size?

This the the most cursed part of modern cpu design, but the TLDR is that programs use virtual addresses while CPUs use physical addresses which means that CPU caches need to include the translation from virtual to physical adress. The problem is that for L1 cache, the latency requirement of 3-4 cycles is too strict to first do a TLB lookup and then an L1 cache lookup, so the L1 can only be keyed on the bits of ram wh…

Can you not take some of those virtual bits and get more buckets that way? I am sure it will make things more complicated if nothing else by them possibly being mapped to the same physical page, but it doesn't sound like an impossible barrier. Maybe something terrible where a cache line keeps bouncing between different buckets in the rare case that does happen, but as long as you can keep the common case as fast...

Otoh L1 sizes hasn't increased since my first processor, those CPU designers probably know more than I do.

Re: Arm's Cortex X925: Reaching Desktop Performance

#109

Post by GeekyBear »

pdpi wrote: post #2

Kind of weird to see an article about high-performance ARM cores without a single reference to Apple or how this hardware compares to M4 or M5 cores.

It does make me miss the deep dives for new core designs from Anandtech.

Running the SPEC benchmark interger and floating piitnt suites takes all day, but it's hard to game a benchmark with that much depth.

It's a shame that nobody has been willing to offer that level of detail.

Re: Arm's Cortex X925: Reaching Desktop Performance

#110

Post by wmf »

drzaiusx11 wrote: post #75
llm_nerd wrote: post #36

Earlier quoted context omitted.

The core they're talking about was released about two years ago. nvidia stuck it on their grace blackwell (e.g. DGX Spark) as basically a coordinator on the system. Anyway, here it is in GB10 form- https://browser.geekbench.com/v6/cpu/14078585 And here is a comparable M5 in a laptop- https://browser.geekbench.com/macs/macbook-pro-14-inch-2025 M5 has about a 32% per core advantage, though the DGX obviously has a much…

Afaict the "desktop" target is meaningless these days. Desktops aren't really a thing anymore in the general sense are they? Only folks I know still hanging on to desktop hardware are gamers and even those I see going by the wayside with external video cards becoming more reliable. "Daily driver" is probably a better term, but everyone's daily usage patterns will vary. I could do my day job with a VT100 emulator on a…

The "desktop" market includes laptops but excludes servers, phones, tablets, etc.
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