AMD's Ryzen CPUs might be slower in PC games due to a weird Windows 11 bug

https://www.techradar.com/computing/cpu/amds-ryzen-cpus-might-be-slower-in-pc-games-due-to-a-weird-windows-11-bug-and-while-theres-a-fix-you-absolutely-shouldnt-use-it

by speckx • 2 years ago

88 31 2 years ago

techradar.com

ChoGGi• 2 years ago

The usual consensus I've heard is that UAC is always on even after turning the slider all the way off, while using the admin account doesn't use UAC (changing the EnableLUA in reg also works).

variadix• 2 years ago

Apparently just running the process as Admin works as well

Wowfunhappy2• 2 years ago

This is the first I'm reading that UAC has a performance impact and I'd like to know more.

I have a PC that I literally use for single player games and nothing else (I do not have a web browser installed, or even Steam, games are installed from a network share). I have no use for UAC and I'd like to squeeze everything out of my CPU.

fuzzy22• 2 years ago

If it has a performance impact, that's not on Windows but the software. Many games are really really badly made software, so that's not surprising.

UAC is the single greatest security improvement Microsoft ever created.

ZoomerCretin• 2 years ago

Is there any good reason for Microsoft to not open-source Windows? They are dangerously close to creating the Year of the Linux Desktop if they continue proving Wirth right.

NavinF• 2 years ago

They are dangerously close to creating the Year of the Linux Desktop

How much do you wanna bet? I don't see that happening in the next decade

burnte• 2 years ago

There was a scheduler bug in the early Ryzen days that got fixed, this will too.

tedunangst• 2 years ago

The background for this really puzzles me. AMD said you should be seeing more improvement for zen 5 over zen 4. They go back and forth, AMD says run it as super root. Zen 5 gets faster. But zen 4 gets faster too. The improvement basically disappears again when the "fix" is applied universally. So why was AMD testing with two different setups?

Out_of_Characte3• 2 years ago

The phoronix bench suite showed performance in line of expectations. Its specifically games on windows that regressed. I have no clue how windows scheduler works but that can have a huge impact in games specifically.

anonymoushn• 2 years ago

Compared to Zen4, Zen5 has much higher latency between cores on different chiplets. It's possible that a scheduler + app combo could regress on Zen5 for this reason. It sounds basically impossible for single-threaded apps to be impacted because timeslices are really big. Multithreaded apps where threads are communicating constantly could easily run slower if the scheduler sees all the cores as identical and interchangeable.

I don't know much about this topic, but it seems like Windows uses Processor Groups for scheduling[0], and generally tries to fit each NUMA node into 1 Processor Group (as long as it has at most 64 cores in it). Since the issue here is latency between chiplets and no NUMA is involved, all the cores go in the same Processor Group.

[0] https://learn.microsoft.com/en-us/windows/win32/procthread/p...

Rohansi• 2 years ago

Maybe something to do with Game Mode on Windows.

dathinab• 2 years ago

my guess is there is a bug in Windows related to scheduling which makes Zen 5 slower and by using the admin accounts for testing but comparing to Zen 4 tests results without admin account it was obfuscated.

I mean on Linux Zen 5 seems to be clearly faster then Zen 4 by a good margin.

abhinavk• 2 years ago

Phoronix’s tests of 9950X on Windows and Linux: https://www.phoronix.com/review/ryzen-9950x-windows11-ubuntu

9950X is 14% faster than 7950X on Ubuntu. And 10% faster on Windows.

Ubuntu is 10% faster than Windows on the same hardware.

keyringlight• 2 years ago

CachyOS has also put out a repository of packages compiled for zen4/5 [1], which I'm fairly sure Phoronix has shown an interest in doing an updated comparison against the current x86_64-v2/v3/v4/etc versions

[1] https://discuss.cachyos.org/t/zen-4-5-optimized-repository-t...

loeg• 2 years ago

There is absolutely no detail here. Tl;dr maybe Ryzen CPUs are a handful of percent faster when testing under the admin account instead of non-admin. Is it reproducible? Who knows. What does Windows 11 have to do with it? Who knows. We know nothing after reading the article.

ds• 2 years ago

I believe that disabling core isolation and bitlocker will also give a 2-3% gain as well. Not worth it though for the security loss.

Cold_Miserable• 2 years ago

How is the built-in Administrator account faster than a named account? I wonder if its a bloatware effect. They need to test with all bloatware removed. No control flow guard, defender, firewall, appearance to performance, no sounds, no background, microcode dll's deleted, mitigations disabled in regedit, storport disabled, every service disabled, every app deleted, edge deleted etc.

olliej• 2 years ago

From the article it sounds like it’s a change to scheduling priorities not what is running (from other comments it sounds like there’s a change in latency related to moving processes across cores in different packages?)

AMD's Ryzen CPUs might be slower in PC games due to a weird Windows 11 bug

Related Stories