6 ms·

Windows Server 2025 Runs Better on ARM

187 points by jasoneckert 6mo ago

p_ing 6mo ago
Typical approach on an HV server is to disable C States, set power management to high, etc preventing x86 from downclocking. Keeping the CPU from seesawing can have big improvements. But you’re not going to do that in a lab/personal machine, usually.
- Melatonic 5mo ago
  Or just disable turbo boost
  - p_ing 5mo ago
    That’s not sufficient as you will still downclock.
stackskipton 5mo ago
As former Windows person who still uses fair amount of Powershell on Linux, I was interested. However, reading the summary left me confused like you don't understand what's happening at Microsoft. > Hopefully Microsoft will spend more time in the future on their server product strategy and less on Copilot ;-) The future product strategy is clear, it's Linux for servers. .Net runs on Linux, generally with much better performance. Microsoft internally on Azure is using Linux a ton and Windows Server is legacy and hell, MSSQL is legacy. Sure, they will continue to sell it because if you want to give them thousands of dollars, they would be idiots to turn it down but it's no longer a focus.
- keithnz 5mo ago
  in no way that I can see is MSSQL or Server "legacy".
  - chaps 5mo ago
    On the flip side, every single MSSQL instance that I've encountered has been legacy. For at least five years.
    - Incipient 5mo ago
      For mid sized businesses, where you're mostly just doing some business reporting, a single mssql instance makes for a great and very cheap 'data warehouse'. All the auth magically works for people to connect with Excel, and powerbi+cloud just works out of the box. I'd be curious what a better/non-legacy solution is! (as I do this stuff haha, and don't see much else other than full cloud options, sf etc)
      - chaps 5mo ago
        These days I think airtable and other "no code" systems fit this bill well.
        trollbridge 5mo ago
        MSSQL doesn’t come with usage based pricing.
        chaps 5mo ago
        Sure, but you're just shifting that cost elsewhere. Not defending the no-code services (they're extremely predatory), just that it's not as simple as cost-vs-no-cost.
  - Alupis 5mo ago
    The only people using MSSQL Server are people deep, deep in the Microsoft ecosystem. Think government work, and those unlucky enough to work at a pure Microsoft shop where every problem looks like a Microsoft or Azure solution. It's not a dominant database anywhere on the outside.
    - 5mo ago
- p_ing 5mo ago
  Azure services run on [customized] Hyper-V, thus Windows Server. Azure networking is Linux. EDIT: Marvel at the NT4 style Task Manager [0]. [0] https://techcommunity.microsoft.com/blog/windowsosplatform/azure-host-os-%E2%80%93-cloud-host/3709528 https://techcommunity.microsoft.com/blog/windowsosplatform/a...
  - monocasa 5mo ago
    Microsoft just upstreamed support for running Linux as the Hyper-V equivalent of Dom0, so no Windows required. https://www.phoronix.com/news/Linux-6.19-Improves-Hyper-V https://www.phoronix.com/news/Linux-6.19-Improves-Hyper-V
    - pjmlp 5mo ago
      That is still a very long way until Azure Host OS gets replaced.
  - Melatonic 5mo ago
    Guessing some of Azure networking (or storage controllers) might even be BSD based ?
    - p_ing 5mo ago
      Azure networking is Microsoft's own Linux: Azure Linux [0]. I don't know what they use for storage controllers. [0] https://en.wikipedia.org/wiki/Azure_Linux https://en.wikipedia.org/wiki/Azure_Linux
phwbikm 5mo ago
Cant believe somebody is still using windows server? What’s the use case?
- haik90 5mo ago
  I hope we migrate our stack to Linux soon, but I think that’ll take few years. I know big company that run their core on Windows Server 2012, I’ve no idea how they manage the software assurance and compliance
  - deleted 5mo ago
    [deleted]
  - evanjrowley 5mo ago
    Actually Windows Server 2012 or just Windows Domain functional level? https://learn.microsoft.com/en-us/windows-server/identity/ad-ds/active-directory-functional-levels#windows-server-functional-level-interoperability https://learn.microsoft.com/en-us/windows-server/identity/ad...
- deleted 5mo ago
  [deleted]
- jayd16 5mo ago
  Building Unreal games. Running windows containers. Windows server is actually kind of awesome for when you need a Windows machine. Linux is great for servers but Windows server is the real Windows pro. Rock solid and none of the crap. The worst part of Windows server is knowing that Microsoft can make a good operating system and chooses not to.
  - jamesfinlayson 5mo ago
    Yes I only recently understood why people use Windows Server as a desktop operating system - it looks and feels like old Windows.
    - 5mo ago
bfrog 5mo ago
It all runs better with Linux, Linux isn’t wasting cycles spying on me.
- 7bit 5mo ago
  Very valuable insight.
ntstatusquo 5mo ago
Windows developer here. After reading this post, my gut instinct is that this is due to something called 'segment heap'. A bit of backstory: there are two, totally independent implementations behind the Windows heap allocation APIs (i.e. the implementation code behind RtlHeapAlloc and RtlHeapFree, which are called by malloc/free). The older of the two, developed uring the Dave Cutler era, is known as the "NT heap". The newer implementation, developed in the 2010s, is known as "segment heap". This is all documented online if anyone wants to read more. When development on segment heap was completed, it was known to be superior to the NT heap in many ways. In particular, it was more efficient in terms of memory footprint, due to lower fragmentation-related waste. Segment heap was smarter about reusing small allocations slots that were recently free'd. But, as ever, Windows was very serious about legacy app compat. Joel Spolsky calls this the 'Raymond Chen camp'. So, they didn't want to turn segment heap on universally. It was known that a small portion of legacy software would misbehave and do things like, rely on doing a bit of use-after-free as a treat. Or worse, it took dependencies on casting addresses to internal NT heap data structures. So, the decision at the time was to make segment heap the default for packaged executables. At that time, Windows Phone still existed, and Microsoft was pushing super hard on the Universal platform being the new, recommended way to make apps on Windows. So they thought we'd see a gradual transition from unpackaged executables to packaged, and thus, a gradual transition from NT heap to segment heap. The dream of UWP died, and the Windows framework landscape is more fragmented than ever. Most important software on Windows is still unpackaged, and most of it runs on x64. Why does this matter? Because segment heap is also enabled by default on arm. Same logic as the packaged vs unpackaged decision. Arm64 binaries on Windows are guaranteed not to be ancient, unmaintained legacy code. Arm64 windows devices have been a big success, and users widely report that they feel more responsive than x64 devices. A not insignificant part of why Windows feels better on arm is because segment heap is enabled by default on arm. I'd be interested to see how this test turns out if you force segment heap on x64. You can do it on a per-executable basis via creating a DWORD value named FrontEndHeapDebugOptions under HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options\<myExeName>.exe, and giving it a value of 8. You can turn it on globally for all processes by creating a DWORD value named "Enabled" under HKLM\SYSTEM\CurrentControlSet\Control\Session Manager\Segment Heap, and giving it a value of 3. I do this on my dev machine and have encountered zero problems. The memory footprint savings are pretty crazy. About 15% in my testing.
1970-01-01 5mo ago
>Across multiple runs of each test, the Snapdragon system produced consistent, repeatable timings nearly every time. On the Intel system, results varied significantly, occasionally beating the Snapdragon, but most of the time falling behind. The Snapdragon was the clear winner on each test overall. They blogged everything to generate the setup, including the hunch and test code but the anecdotal results are missing. It's a little suspect. How much faster is ARM??
- jasoneckert 5mo ago
  I intentionally left out screenshots of the output for a couple of reasons: 1) They’d distract from the main point (I wasn’t aiming to write a benchmarking post), and 2) They can be misleading, since results will vary across ARM hardware and even between Snapdragon X Elite variants. Instead, I included the PowerShell snippets so anyone interested can reproduce the results themselves. For a rough sense of the outcome: the Snapdragon VM outperformed the Intel VM by ~20–80%, depending on the test (DNS ~20%, IIS ~50%, all others closer to ~80%).
  - jiggawatts 5mo ago
    You likely tripped over a difference in power management profiles (and capabilities) between Intel and ARM. You're testing "variability" and latency, and you even mention that "modern Intel CPUs tend to ramp frequency..." but entirely neglect to mention which specific Windows Power Profile you were using. Fundamentally, you're benchmarking a server operating system on laptops and/or desktop-class hardware, and not the same spec either. I.e.: you're not controlling for differences in memory bandwidth, SSD performance, etc... Even on server hardware the power profiles matter! A lot more than you think! One of my gimmicks in my consulting gig is to change Intel server power settings from "Balanced" to "Maximum Performance" and gloat as the customer makes the Shocked Pikachu face because their $$$ "enterprise grade server" instantly triples in performance for the cost of a button press. Not to mention that by testing this in VMs, you're benchmarking three layers: The outer OS (and its power management), the hypervisor stack, and the inner guest OS.
    - 5mo ago
nubinetwork 5mo ago
> Like many ARM systems, it doesn’t chase high boost clocks and instead delivers steady, sustained performance Maybe not boost clocks, but every arm system I've used supports some form of frequency scaling and behaves the same as any x86 machine I've used in comparison. The only difference is how high can you go... /shrug
- SOLAR_FIELDS 5mo ago
  I am not sure how workload specific it is, but in cloud compute in organizations I've worked there's often been a substantial savings outlay from literally just switching from x86 machines for workloads to ARM machines, with no other changes. So it's usually twofold, and a combination of both (lower price for the instance, but also better efficiency as well). In one organization in particular of recent memory we were doing dynamic autoscaling of hundreds of kubernetes nodes simultaneously and were able to project / achieve about 15% conservatively. Just from going x86 -> ARM with no additional changes. Probably some workload that is CPU bound but does not depend on x86 architecturally would benefit from a number significantly higher than that 15%
josephg 5mo ago
What is the RAM and storage on each of these machines? Is it possible the Snapdragon has packaged RAM (with faster interconnects as a result), and the x86 machine is using DIMMs with longer traces? And what about storage? For that matter, what CPUs are you using? Its possible ARM is a better architecture. But a lot of benchmarks end up stressing one part of the system more than any other. And if thats the case, faster RAM or faster syscalls or faster SSD performance or something could be whats really driving this performance difference.
- jasoneckert 5mo ago
  Both systems have DDR5 soldered to the mainboard and NVMe SSDs (the Intel system has a faster Samsung model compared to the Foresee model in the Snapdragon system).
  - josephg 5mo ago
    What CPUs are they both running? Is the ARM chip simply faster?
  - Melatonic 5mo ago
    Would be good test those SSD to see when they thermally throttle. Most hit pretty fast (on desktop drives it's quite easy to add heat sinks and they make a big difference)
    - josephg 5mo ago
      Yep. There's lots of things I'd want to test before assuming the ARM architecture is fundamentally better than x86 in some way.
whatever1 5mo ago
I mean we were suspecting for some time that smartphone processors have reached parity with laptop class ones. MacBook Neo proved it. Not clear how both Amd and Intel not only lost the smartphone fight but also lost in their own field (aka servers, laptops, desktops) 15 years ago if I told you that windows would be running better on ARM you would call me crazy.
- deleted 5mo ago
  [deleted]
- throwa356262 5mo ago
  According to CPU bench, the Neo CPU is about the same speed as a mid range intel laptop CPU from 4 years ago. Apple A18 Pro (Q1 2026): Multithread 11977, Single Thread 4043 Intel Core i5-1235U (Q1 2022): Multithread 12605, Single Thread 3084 -- On the high-end we got i9-13900KS at about 60k, M5 Max 18 scores about the same. But when you move on to server CPUs like Threadripper and EPYC things are about 3x faster. Lets see if the brand new Arm AGI changes this situation in a few months.
  - attentive 5mo ago
    I look at those numbers and think that A18 pro is 25% faster as single thread is what matters for UX. browserbench speedometer 3.0 on A18 pro - 33, Intel Core i5-1235U - 22 i9-13900KS gets about 33 M4 Pro - 44-50
    - throwa356262 5mo ago
      You can't compare raw CPU speed by measuring different browsers on different OSes :) Try this: https://www.cpubenchmark.net/compare/6693vs7115vs7229vs7232/AMD-Ryzen-Threadripper-PRO-9995WX-vs-AMD-Ryzen-9-9950X3D2-vs-Apple-M5-Pro-18-Core-vs-Apple-A18-Pro-(MacBook-Neo) https://www.cpubenchmark.net/compare/6693vs7115vs7229vs7232/...
      - whatever1 5mo ago
gt0 5mo ago
Am I missing something or is the article avoiding saying what Intel processor they are using?
- wmf 5mo ago
  14th Gen Intel Core i9
  - gt0 5mo ago
    That's what I mean, no actual processor model.
cloudbonsai 5mo ago
Reading the article, it seems to boil down to the following two observations: 1. ARM64 is actually less "smart" than x64. While Intel's Core i9 tries to be clever by aggressive boosting and throttling, Snapdragon just delivers steady and consistent performance. This lack of variability makes it easier for the OS to schedule tasks. 2. It is possible that the ARM build is more efficient than the x64 build, because Windows has less historical clutter on ARM than x64. So, has CPU throttling become too smart to the point it hurts?
- adrian_b 5mo ago
  It should be noted that this is a server OS, but it has been tested on a desktop x86 CPU. The x86 server CPUs, like AMD Epyc or Intel Xeon, have a lower range within which the clock frequency may vary and their policies for changing the clock frequency are less aggressive than for desktop CPUs, so they provide a more constant and predictable performance, which favors multi-threaded workloads, unlike in desktop CPUs, where the clock frequency control algorithms are tuned for obtaining the best single-thread performance, even if that hurts multi-threaded performance.
  - cloudbonsai 5mo ago
    That makes a lot of sense! > The x86 server CPUs, like AMD Epyc or Intel Xeon, have a lower range within which the clock frequency may vary and their policies for changing the clock frequency are less aggressive than for desktop CPUs Probably we need to compare Xeon/EPYC with something like AWS Graviton or Ampere Altra to get an accurate picture here. That said, I think "Windows Server works fast on Snapdragon" is both crazy and fascinating; I wasn't even sure if that was possible.
doctorpangloss 5mo ago
you upgraded a windows 2022 system to windows 2025, and you are comparing the upgraded machine, which will not have 2025 optimized defaults, including a lot of stuff that makes VMs work much better, to a new 2025 installation, right?
c0l0 5mo ago
Does Windows on ARM use VBS/Virtualization Based Security, and does ARM support nested virtualization to do so in a VM, too? Does it employ costly CPU vulnerability mitigation techniques that might hit two times in a VM (unless the Hypervisor is adequately set up, which I'd hope is the default for Hyper-V)? Those two things account for most of the common performance problems observed when putting modern Windows in a VM. I'd love to know more about it, but the article does not seem to mention either.
opentokix 5mo ago
It is probably because the ram on his laptop is so much faster.
adrian_b 5mo ago
If indeed the supposition that the less variable and more predictable performance of the ARM CPU mattered for the observed system behavior is right, then using an x86 server CPU, e.g. an Epyc CPU, instead of a desktop CPU would provide similar benefits to the ARM CPU, because server CPUs have a lower range of variation for the clock frequency and they use less aggressive clock frequency boosting policies. This could be tested even on the existing desktop hardware, by disabling "Turbo" in the BIOS settings, so that the Intel CPU would run at the base clock frequency, providing a lower, but stable and predictable performance.
- chronogram 5mo ago
  You can also disable turbo behaviour in the power plan. The setting might not be available in the GUI by default though.
trynumber9 5mo ago
@jasoneckert For the sake of science, can you disable your e cores and try this test again?
fortran77 5mo ago
I love Windows on Arm. Except for a few edge cases with specialized device drivers, everything just works much better. My Widnows Arm Laptops feel fast and the battery lasts all day. The biggest reason I still keep a Xeon and Threadripper server around is NVidia support.
upboundspiral 5mo ago
While interesting the post is incredibly vague and jumps to conclusions that in my opinion other data can explan or at least requires further testing. 14th gen intel have "big" and "little" cores. Unless you specify to pin cores in the VM, if at any point the virtualization swaps cores then your X86 performance on Intel goes down the drain. Also laptop perfomance is incredibly suspect. Not only does cooling, etc have huge effects, but Intel is clearly behind AMD since many years (14th gen is a refresh of an old architecture). Laptop benchmark: https://www.phoronix.com/review/snapdragon-x1e-september https://www.phoronix.com/review/snapdragon-x1e-september Server benchmarks: https://www.phoronix.com/review/ampereone-a192-32x/12 https://www.phoronix.com/review/ampereone-a192-32x/12 https://www.phoronix.com/review/google-axion-c4a/5 https://www.phoronix.com/review/google-axion-c4a/5 Based on server performance while ARM is making strides, AMD still has the performance crown.

187 points by jasoneckert 6mo ago

p_ing 6mo ago

Typical approach on an HV server is to disable C States, set power management to high, etc preventing x86 from downclocking. Keeping the CPU from seesawing can have big improvements. But you’re not going to do that in a lab/personal machine, usually.

Melatonic 5mo ago
Or just disable turbo boost
- p_ing 5mo ago
  That’s not sufficient as you will still downclock.

stackskipton 5mo ago

As former Windows person who still uses fair amount of Powershell on Linux, I was interested. However, reading the summary left me confused like you don't understand what's happening at Microsoft. > Hopefully Microsoft will spend more time in the future on their server product strategy and less on Copilot ;-) The future product strategy is clear, it's Linux for servers. .Net runs on Linux, generally with much better performance. Microsoft internally on Azure is using Linux a ton and Windows Server is legacy and hell, MSSQL is legacy. Sure, they will continue to sell it because if you want to give them thousands of dollars, they would be idiots to turn it down but it's no longer a focus.

keithnz 5mo ago
in no way that I can see is MSSQL or Server "legacy".
- chaps 5mo ago
  On the flip side, every single MSSQL instance that I've encountered has been legacy. For at least five years.
  - Incipient 5mo ago
    For mid sized businesses, where you're mostly just doing some business reporting, a single mssql instance makes for a great and very cheap 'data warehouse'. All the auth magically works for people to connect with Excel, and powerbi+cloud just works out of the box. I'd be curious what a better/non-legacy solution is! (as I do this stuff haha, and don't see much else other than full cloud options, sf etc)
    - chaps 5mo ago
      These days I think airtable and other "no code" systems fit this bill well.
      - trollbridge 5mo ago
        MSSQL doesn’t come with usage based pricing.
        chaps 5mo ago
        Sure, but you're just shifting that cost elsewhere. Not defending the no-code services (they're extremely predatory), just that it's not as simple as cost-vs-no-cost.
- Alupis 5mo ago
  The only people using MSSQL Server are people deep, deep in the Microsoft ecosystem. Think government work, and those unlucky enough to work at a pure Microsoft shop where every problem looks like a Microsoft or Azure solution. It's not a dominant database anywhere on the outside.
  - 5mo ago
p_ing 5mo ago
Azure services run on [customized] Hyper-V, thus Windows Server. Azure networking is Linux. EDIT: Marvel at the NT4 style Task Manager [0]. [0] https://techcommunity.microsoft.com/blog/windowsosplatform/azure-host-os-%E2%80%93-cloud-host/3709528 https://techcommunity.microsoft.com/blog/windowsosplatform/a...
- monocasa 5mo ago
  Microsoft just upstreamed support for running Linux as the Hyper-V equivalent of Dom0, so no Windows required. https://www.phoronix.com/news/Linux-6.19-Improves-Hyper-V https://www.phoronix.com/news/Linux-6.19-Improves-Hyper-V
  - pjmlp 5mo ago
    That is still a very long way until Azure Host OS gets replaced.
- Melatonic 5mo ago
  Guessing some of Azure networking (or storage controllers) might even be BSD based ?
  - p_ing 5mo ago
    Azure networking is Microsoft's own Linux: Azure Linux [0]. I don't know what they use for storage controllers. [0] https://en.wikipedia.org/wiki/Azure_Linux https://en.wikipedia.org/wiki/Azure_Linux

phwbikm 5mo ago

Cant believe somebody is still using windows server? What’s the use case?

haik90 5mo ago
I hope we migrate our stack to Linux soon, but I think that’ll take few years. I know big company that run their core on Windows Server 2012, I’ve no idea how they manage the software assurance and compliance
- deleted 5mo ago
  [deleted]
- evanjrowley 5mo ago
  Actually Windows Server 2012 or just Windows Domain functional level? https://learn.microsoft.com/en-us/windows-server/identity/ad-ds/active-directory-functional-levels#windows-server-functional-level-interoperability https://learn.microsoft.com/en-us/windows-server/identity/ad...
deleted 5mo ago
[deleted]
jayd16 5mo ago
Building Unreal games. Running windows containers. Windows server is actually kind of awesome for when you need a Windows machine. Linux is great for servers but Windows server is the real Windows pro. Rock solid and none of the crap. The worst part of Windows server is knowing that Microsoft can make a good operating system and chooses not to.
- jamesfinlayson 5mo ago
  Yes I only recently understood why people use Windows Server as a desktop operating system - it looks and feels like old Windows.
  - 5mo ago

bfrog 5mo ago

It all runs better with Linux, Linux isn’t wasting cycles spying on me.

7bit 5mo ago
Very valuable insight.

ntstatusquo 5mo ago

Windows developer here. After reading this post, my gut instinct is that this is due to something called 'segment heap'. A bit of backstory: there are two, totally independent implementations behind the Windows heap allocation APIs (i.e. the implementation code behind RtlHeapAlloc and RtlHeapFree, which are called by malloc/free). The older of the two, developed uring the Dave Cutler era, is known as the "NT heap". The newer implementation, developed in the 2010s, is known as "segment heap". This is all documented online if anyone wants to read more. When development on segment heap was completed, it was known to be superior to the NT heap in many ways. In particular, it was more efficient in terms of memory footprint, due to lower fragmentation-related waste. Segment heap was smarter about reusing small allocations slots that were recently free'd. But, as ever, Windows was very serious about legacy app compat. Joel Spolsky calls this the 'Raymond Chen camp'. So, they didn't want to turn segment heap on universally. It was known that a small portion of legacy software would misbehave and do things like, rely on doing a bit of use-after-free as a treat. Or worse, it took dependencies on casting addresses to internal NT heap data structures. So, the decision at the time was to make segment heap the default for packaged executables. At that time, Windows Phone still existed, and Microsoft was pushing super hard on the Universal platform being the new, recommended way to make apps on Windows. So they thought we'd see a gradual transition from unpackaged executables to packaged, and thus, a gradual transition from NT heap to segment heap. The dream of UWP died, and the Windows framework landscape is more fragmented than ever. Most important software on Windows is still unpackaged, and most of it runs on x64. Why does this matter? Because segment heap is also enabled by default on arm. Same logic as the packaged vs unpackaged decision. Arm64 binaries on Windows are guaranteed not to be ancient, unmaintained legacy code. Arm64 windows devices have been a big success, and users widely report that they feel more responsive than x64 devices. A not insignificant part of why Windows feels better on arm is because segment heap is enabled by default on arm. I'd be interested to see how this test turns out if you force segment heap on x64. You can do it on a per-executable basis via creating a DWORD value named FrontEndHeapDebugOptions under HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options\<myExeName>.exe, and giving it a value of 8. You can turn it on globally for all processes by creating a DWORD value named "Enabled" under HKLM\SYSTEM\CurrentControlSet\Control\Session Manager\Segment Heap, and giving it a value of 3. I do this on my dev machine and have encountered zero problems. The memory footprint savings are pretty crazy. About 15% in my testing.

1970-01-01 5mo ago

>Across multiple runs of each test, the Snapdragon system produced consistent, repeatable timings nearly every time. On the Intel system, results varied significantly, occasionally beating the Snapdragon, but most of the time falling behind. The Snapdragon was the clear winner on each test overall. They blogged everything to generate the setup, including the hunch and test code but the anecdotal results are missing. It's a little suspect. How much faster is ARM??

jasoneckert 5mo ago
I intentionally left out screenshots of the output for a couple of reasons: 1) They’d distract from the main point (I wasn’t aiming to write a benchmarking post), and 2) They can be misleading, since results will vary across ARM hardware and even between Snapdragon X Elite variants. Instead, I included the PowerShell snippets so anyone interested can reproduce the results themselves. For a rough sense of the outcome: the Snapdragon VM outperformed the Intel VM by ~20–80%, depending on the test (DNS ~20%, IIS ~50%, all others closer to ~80%).
- jiggawatts 5mo ago
  You likely tripped over a difference in power management profiles (and capabilities) between Intel and ARM. You're testing "variability" and latency, and you even mention that "modern Intel CPUs tend to ramp frequency..." but entirely neglect to mention which specific Windows Power Profile you were using. Fundamentally, you're benchmarking a server operating system on laptops and/or desktop-class hardware, and not the same spec either. I.e.: you're not controlling for differences in memory bandwidth, SSD performance, etc... Even on server hardware the power profiles matter! A lot more than you think! One of my gimmicks in my consulting gig is to change Intel server power settings from "Balanced" to "Maximum Performance" and gloat as the customer makes the Shocked Pikachu face because their $$$ "enterprise grade server" instantly triples in performance for the cost of a button press. Not to mention that by testing this in VMs, you're benchmarking three layers: The outer OS (and its power management), the hypervisor stack, and the inner guest OS.
  - 5mo ago

nubinetwork 5mo ago

> Like many ARM systems, it doesn’t chase high boost clocks and instead delivers steady, sustained performance Maybe not boost clocks, but every arm system I've used supports some form of frequency scaling and behaves the same as any x86 machine I've used in comparison. The only difference is how high can you go... /shrug

SOLAR_FIELDS 5mo ago
I am not sure how workload specific it is, but in cloud compute in organizations I've worked there's often been a substantial savings outlay from literally just switching from x86 machines for workloads to ARM machines, with no other changes. So it's usually twofold, and a combination of both (lower price for the instance, but also better efficiency as well). In one organization in particular of recent memory we were doing dynamic autoscaling of hundreds of kubernetes nodes simultaneously and were able to project / achieve about 15% conservatively. Just from going x86 -> ARM with no additional changes. Probably some workload that is CPU bound but does not depend on x86 architecturally would benefit from a number significantly higher than that 15%

josephg 5mo ago

What is the RAM and storage on each of these machines? Is it possible the Snapdragon has packaged RAM (with faster interconnects as a result), and the x86 machine is using DIMMs with longer traces? And what about storage? For that matter, what CPUs are you using? Its possible ARM is a better architecture. But a lot of benchmarks end up stressing one part of the system more than any other. And if thats the case, faster RAM or faster syscalls or faster SSD performance or something could be whats really driving this performance difference.

jasoneckert 5mo ago
Both systems have DDR5 soldered to the mainboard and NVMe SSDs (the Intel system has a faster Samsung model compared to the Foresee model in the Snapdragon system).
- josephg 5mo ago
  What CPUs are they both running? Is the ARM chip simply faster?
- Melatonic 5mo ago
  Would be good test those SSD to see when they thermally throttle. Most hit pretty fast (on desktop drives it's quite easy to add heat sinks and they make a big difference)
  - josephg 5mo ago
    Yep. There's lots of things I'd want to test before assuming the ARM architecture is fundamentally better than x86 in some way.

whatever1 5mo ago

I mean we were suspecting for some time that smartphone processors have reached parity with laptop class ones. MacBook Neo proved it. Not clear how both Amd and Intel not only lost the smartphone fight but also lost in their own field (aka servers, laptops, desktops) 15 years ago if I told you that windows would be running better on ARM you would call me crazy.

deleted 5mo ago
[deleted]
throwa356262 5mo ago
According to CPU bench, the Neo CPU is about the same speed as a mid range intel laptop CPU from 4 years ago. Apple A18 Pro (Q1 2026): Multithread 11977, Single Thread 4043 Intel Core i5-1235U (Q1 2022): Multithread 12605, Single Thread 3084 -- On the high-end we got i9-13900KS at about 60k, M5 Max 18 scores about the same. But when you move on to server CPUs like Threadripper and EPYC things are about 3x faster. Lets see if the brand new Arm AGI changes this situation in a few months.
- attentive 5mo ago
  I look at those numbers and think that A18 pro is 25% faster as single thread is what matters for UX. browserbench speedometer 3.0 on A18 pro - 33, Intel Core i5-1235U - 22 i9-13900KS gets about 33 M4 Pro - 44-50
  - throwa356262 5mo ago
    You can't compare raw CPU speed by measuring different browsers on different OSes :) Try this: https://www.cpubenchmark.net/compare/6693vs7115vs7229vs7232/AMD-Ryzen-Threadripper-PRO-9995WX-vs-AMD-Ryzen-9-9950X3D2-vs-Apple-M5-Pro-18-Core-vs-Apple-A18-Pro-(MacBook-Neo) https://www.cpubenchmark.net/compare/6693vs7115vs7229vs7232/...
    - whatever1 5mo ago

gt0 5mo ago

Am I missing something or is the article avoiding saying what Intel processor they are using?

wmf 5mo ago
14th Gen Intel Core i9
- gt0 5mo ago
  That's what I mean, no actual processor model.

cloudbonsai 5mo ago

Reading the article, it seems to boil down to the following two observations: 1. ARM64 is actually less "smart" than x64. While Intel's Core i9 tries to be clever by aggressive boosting and throttling, Snapdragon just delivers steady and consistent performance. This lack of variability makes it easier for the OS to schedule tasks. 2. It is possible that the ARM build is more efficient than the x64 build, because Windows has less historical clutter on ARM than x64. So, has CPU throttling become too smart to the point it hurts?

adrian_b 5mo ago
It should be noted that this is a server OS, but it has been tested on a desktop x86 CPU. The x86 server CPUs, like AMD Epyc or Intel Xeon, have a lower range within which the clock frequency may vary and their policies for changing the clock frequency are less aggressive than for desktop CPUs, so they provide a more constant and predictable performance, which favors multi-threaded workloads, unlike in desktop CPUs, where the clock frequency control algorithms are tuned for obtaining the best single-thread performance, even if that hurts multi-threaded performance.
- cloudbonsai 5mo ago
  That makes a lot of sense! > The x86 server CPUs, like AMD Epyc or Intel Xeon, have a lower range within which the clock frequency may vary and their policies for changing the clock frequency are less aggressive than for desktop CPUs Probably we need to compare Xeon/EPYC with something like AWS Graviton or Ampere Altra to get an accurate picture here. That said, I think "Windows Server works fast on Snapdragon" is both crazy and fascinating; I wasn't even sure if that was possible.

doctorpangloss 5mo ago

you upgraded a windows 2022 system to windows 2025, and you are comparing the upgraded machine, which will not have 2025 optimized defaults, including a lot of stuff that makes VMs work much better, to a new 2025 installation, right?

c0l0 5mo ago

Does Windows on ARM use VBS/Virtualization Based Security, and does ARM support nested virtualization to do so in a VM, too? Does it employ costly CPU vulnerability mitigation techniques that might hit two times in a VM (unless the Hypervisor is adequately set up, which I'd hope is the default for Hyper-V)? Those two things account for most of the common performance problems observed when putting modern Windows in a VM. I'd love to know more about it, but the article does not seem to mention either.

opentokix 5mo ago

It is probably because the ram on his laptop is so much faster.

adrian_b 5mo ago

If indeed the supposition that the less variable and more predictable performance of the ARM CPU mattered for the observed system behavior is right, then using an x86 server CPU, e.g. an Epyc CPU, instead of a desktop CPU would provide similar benefits to the ARM CPU, because server CPUs have a lower range of variation for the clock frequency and they use less aggressive clock frequency boosting policies. This could be tested even on the existing desktop hardware, by disabling "Turbo" in the BIOS settings, so that the Intel CPU would run at the base clock frequency, providing a lower, but stable and predictable performance.

chronogram 5mo ago
You can also disable turbo behaviour in the power plan. The setting might not be available in the GUI by default though.

trynumber9 5mo ago

@jasoneckert For the sake of science, can you disable your e cores and try this test again?

fortran77 5mo ago

I love Windows on Arm. Except for a few edge cases with specialized device drivers, everything just works much better. My Widnows Arm Laptops feel fast and the battery lasts all day. The biggest reason I still keep a Xeon and Threadripper server around is NVidia support.

upboundspiral 5mo ago

While interesting the post is incredibly vague and jumps to conclusions that in my opinion other data can explan or at least requires further testing. 14th gen intel have "big" and "little" cores. Unless you specify to pin cores in the VM, if at any point the virtualization swaps cores then your X86 performance on Intel goes down the drain. Also laptop perfomance is incredibly suspect. Not only does cooling, etc have huge effects, but Intel is clearly behind AMD since many years (14th gen is a refresh of an old architecture). Laptop benchmark: https://www.phoronix.com/review/snapdragon-x1e-september https://www.phoronix.com/review/snapdragon-x1e-september Server benchmarks: https://www.phoronix.com/review/ampereone-a192-32x/12 https://www.phoronix.com/review/ampereone-a192-32x/12 https://www.phoronix.com/review/google-axion-c4a/5 https://www.phoronix.com/review/google-axion-c4a/5 Based on server performance while ARM is making strides, AMD still has the performance crown.