Hacker News new | comments | show | ask | jobs | submit login
[dupe] Microsoft: Haswell and older CPUs are slowed down significantly by Spectre fixes (hothardware.com)
57 points by bhouston 11 months ago | hide | past | web | favorite | 30 comments



How convenient for Intel - they have been unable to improve significantly on the single threaded performance since the 4790K but with this "fix", newer CPUs will magically start to look better than the old ones..


Let’s see what happens with AMD.

It’s vulnerable to Spectre even to Variant 2 but they define it as a very low risk what ever that means and only issuing fixes for Variant 1.

It looks like the second variant of Spectre the out of bounds check is the culprit here; if AMD isn’t vulnerable at all it would be great but to me it looks like they are sitting on the fence to wait and see where the exploits go.


And my main system is one such 4790K, which would still have been fine for a few years, but I guess I'm looking at 2019/Zen2 now.


don´t give them ideas... I see great new benchmarks with every security-incident.


Do Microsoft etc see this as an opportunity in disguise perhaps? A problem out of their hands, that's not their fault, that might make people think about upgrading their machines. And the best bit is that it also effects your competitors.


I was thinking exactly the same thing, but regarding the OS rather than machines. It's their best excuse for making everyone upgrade to Windows 10.


I don't think Windows runs faster than Windows 7. It's only by forcing people to upgrade their machine that Microsoft will manage to force people to give up 7 for 10.


Windows 10 is faster than Windows 7:

>Older versions of Windows have a larger performance impact because Windows 7 and Windows 8 have more user-kernel transitions because of legacy design decisions, such as all font rendering taking place in the kernel.

From: https://cloudblogs.microsoft.com/microsoftsecure/2018/01/09/...


Font rendering taking place in the kernel does indeed look quite like a legacy design decision.


It's also kinda ironic because improved performance was the reason behind that decision.


To be honest it might still have better performance if/when they add more mitigations for more security vulnerabilities. It seems like an anomaly right now since they're only addressing Meltdown/Spectre, but the core issues (no pun intended) are fundamentally there.


> I don't think Windows runs faster than Windows 7.

They're claiming the opposite:

>> With Windows 10 [...] we expect that some users will notice a decrease in system performance.

>> With Windows 8 and Windows 7 [...] we expect most users to notice a decrease in system performance.

>> Older versions of Windows have a larger performance impact because Windows 7 and Windows 8 have more user-kernel transitions because of legacy design decisions, such as all font rendering taking place in the kernel.


> This means the typical home and business PC user should not see significant slowdowns in common tasks such as reading email, writing a document or accessing digital photos.

How can Intel possibly continue to claim this when the majority of home and business PC users are on Windows, and probably mostly on hardware older than Skylake too?


For most of those users the affected part of the system is not a key bottleneck: syscalls such as filesystem or hardware access.

For most home/office tasks (web browsing, email, office documents) most of the time is spent waiting for user input or network responses. Even on a really slow old Atom-based netbook I suspect that the difference will be at worst "noticeable" and not significant for these tasks (i.e. it isn't going to make any difference while the app is waiting for your next key-press).

Older games that make many small calls to the graphics hardware will be affected but unless you are running them on really old hardware you'll not notice that either as they won't tax newer hardware even with the extra work. Newer games will be using more efficient techniques anyway.

Startup times are likely to be affected, both OS and individual application, but that is generally a once-per-session matter, and of course there will be some applications (or some workflows using applications otherwise relatively unaffected) that will see a difference, but not the majority.

Older OSs may be more starkly affected because of design changes since. For instance until 10 Windows performed font parsing and rendering in the kernel so text heavy applications might see some extra display lag after these patches. Low-memory situations might be more affected too, as RAM starvation increases the amount of IO happening during normal operation.

Developers are far more likely to notice, I've seen some bad before/after benchmarks for build processes. Long-running tasks, particularly those performing IO such as video encoding, are more likely to make the differences visible too (10% extra on a many-hour encoding task could add up to something pretty inconvenient). It is expected that certain server loads are going to be the worst hit. But none of this paragraph's "things that will be affected" are typical home/business use cases for the majority.


CPU performance isn't important for 'typical home and business' tasks.

They're estimating 6% slowdown based on SYSmark 2014. I quickly skimmed the whitepaper and think this is probably reasonable; there's a mix of CPU-bound and I/O-bound tasks, and the CPU-bound tasks won't be impacted. Most home users are still on spinning disks, so that's your bottleneck for I/O, not the additional syscall overhead.

A 6% slowdown is imperceptible to a human. For tasks that don't need a lot of CPU power (like office applications and web browsing) even a 30% slowdown is not that big a deal.


Haswell and older will see more-significant slowdowns, Skylake and newer will see less-significant slowdowns... what about Broadwell? I have a 6850k.


6850k has launch date 2016. So you are fine.

Microsoft claims CPUs post 2015 only have unnoticable slowdown.


I have a i7 5500 so I am also interested in this. Broadwell is a shrink of Haswell (22nm->14nm), a "tick" in intel terminology. So Broadwell users might not be that lucky?


Great, thanks! I'm mainly on Ubuntu anyways, so I'll still have to see how I'm affected when I update my microcode.


On the bright side, finally a reason for me to upgrade my desktop 3770k?


> finally a reason for me to spend money although everything previously worked

FTFY


yeah, you're right there. in actuality i still can't pull the trigger, it's a perfectly fine machine and nearly 5 years old if i remember right.

it could do with a pcie sdd and maybe a gpu upgrade but it's still perfectly serviceable. the only thing that has failed is the motherboard (was able to replace that for 110 AUD) and the CPU fan (i bought the wrong one and burned the bearings out because it was for lower TDP cpus).


Still rocking my 3770K here too - that thing is rock solid.


Was hoping to see some benchmarks, or at least rough percentages. Sounds like vague marketing-speak.

All I really know is that it won't be faster--thanks.


The wording re. the difference between Windows 10 and 7 seems intriguing:

> Windows 10 PCs with Haswell or older processors will see "more significant slowdowns" and Microsoft notes that a segment of customers may "notice a decrease in system performance”. > Windows 7 and Windows 8 PCs powered by Haswell or older processors will see a "decrease in system performance" for "most users".

Does it mean that if you care about performance, it's better to use Windows 7 instead of 10? It's not spelled out explicitly, but they way they worded it suggests so.


The original post offers some more details on this matter:

> For context, on newer CPUs such as on Skylake and beyond, Intel has refined the instructions used to disable branch speculation to be more specific to indirect branches, reducing the overall performance penalty of the Spectre mitigation. Older versions of Windows have a larger performance impact because Windows 7 and Windows 8 have more user-kernel transitions because of legacy design decisions, such as all font rendering taking place in the kernel. We will publish data on benchmark performance in the weeks ahead.

Source: https://cloudblogs.microsoft.com/microsoftsecure/2018/01/09/...


It's the opposite way around. If you read it closely they say on windows 10, some customers may see a decrease in performance, but for windows 7, most customers will see a decrease.

An article in the verge states "Windows 7 and Windows 8 will be the worst hit simply because these older operating systems have features like kernel-level font rendering that will be impacted by the Spectre and Meltdown mitigations even further than Windows 10."


From the original blog release

> Older versions of Windows have a larger performance impact because Windows 7 and Windows 8 have more user-kernel transitions because of legacy design decisions, such as all font rendering taking place in the kernel. We will publish data on benchmark performance in the weeks ahead.


I interpreted it the opposite. Maybe someone can clarify. The question is why would there be a difference between Win7/8/10 - it's afterall the same WinNT kernel architecture and has the same HAL hardware abstraction layer, it's a matured software code base, so any fix should be possible on all supported versions in the same perfection.


Alternatively: It could be that Windows 10 has various performance optimisations that Windows 7 does not, and these have had to be undone as part of the fix.

In other words: If the fix would cause Windows 7 to lose X% performance, Windows 10 would lose that same X% plus any Y% advantage it had over Windows 7.

(This is just a guess, of course.)




Guidelines | FAQ | Support | API | Security | Lists | Bookmarklet | Legal | Apply to YC | Contact

Search: