Wednesday, October 6th 2021

AMD Processors Lose 15% Gaming Performance with Windows 11, L3 Cache Latency Tripled

Apparently, AMD processors officially compatible with Windows 11, exhibit a three-times increase in L3 cache latency with the new operating system. The new operating system is also found to break the "preferred cores" system on AMD processors (UEFI CPPC2), in which the two "best" CPU cores, which can sustain the highest boost frequencies, are highlighted to the operating system, so most of the light-threaded traffic could be sent to them.

AMD and Microsoft jointly made this discovery, and listed out potential impact on application performance. The increased L3 cache latency affects performance of applications sensitive to memory performance. They also warn of a 10-15% loss in gaming performance. On the other hand, a dysfunctional "preferred cores" system would mean reduced performance in light-threaded tasks as the OS is unaware which are the processor's two best cores. Thankfully, both issues can be fixed via software updates, and AMD is working with Microsoft to push fixes for both issues through Windows Update, in an update rollout scheduled within October 2021.
Source: AMD
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141 Comments on AMD Processors Lose 15% Gaming Performance with Windows 11, L3 Cache Latency Tripled

#1
zlobby
Tip of the iceberg...
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#3
TheLostSwede
Hang on, wasn't Windows 11 tested by expert users, so we wouldn't have problems like this?

Also, some network cards are apparently having issues, specifically Intel's Killer NICs, which is a bit ironic...
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#5
billeman
It's worse than that. W11 even assign threads to the same core when there are other cores free. Try cinebench R20 with 8 threads on a 5950x and watch task manager and/or compare it to W10.

Microsoft really messed it up trying to please Intel.
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#6
windwhirl
TheLostSwedeHang on, wasn't Windows 11 tested by expert users, so we wouldn't have problems like this?

Also, some network cards are apparently having issues, specifically Intel's Killer NICs, which is a bit ironic...
If anything, I detected this months ago and made the corresponding report through Feedback Hub at the time
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#7
Metroid
All right, now I wonder where is this 15% performance loss? so far benchmarks I have done, have no regression x windows 10, all within a margin of error.
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#8
billeman
MetroidAll right, now I wonder where is this 15% performance loss? so far benchmarks I have done, have no regression x windows 10, all within a margin of error.
Try with less threads than your cpu has.
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#9
Metroid
billemanTry with less threads than your cpu has.
Give me examples on how to find out, what you wrote = single thread would apply and single thread tests are fine. I have a 5900, it has 24 threads.
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#10
Arc1t3ct
Things seem to be getting worse and worse for this poor cpu underdog...
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#11
windwhirl
MetroidAll right, now I wonder where is this 15% performance loss? so far benchmarks I have done, have no regression x windows 10, all within a margin of error.
It's not really all that noticeable. You need to hit the L3 cache really hard to notice. Everything else seems unaffected.
Hence why this is only immediately noticeable on AIDA64's benchmark
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#12
billEST
80% are intel in the world, microsoft optime intel first !!!
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#13
billeman
MetroidGive me examples on how to find out, what you wrote = single thread would apply and single thread tests are fine. I have a 5900, it has 24 threads.
For example , W11 cinebenchR20 with 4-8-12-16 threads and compare with WIN10 ? on my 5950x I get ~25% difference from 4 up to 16 threads, so I'd guess this may happen to you up to 12. Might not be happening to you at all though, due to CPPC and CPU etc. differences.
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#14
DeathtoGnomes
TheLostSwedeHang on, wasn't Windows 11 tested by expert users, so we wouldn't have problems like this?

Also, some network cards are apparently having issues, specifically Intel's Killer NICs, which is a bit ironic...
its really a conspiracy, they were intel fanbois.

/tinhat off.
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#16
cyberloner
interface change all with same engine and downgrade ........... lol
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#17
windwhirl
xkm1948New security features?
No. The security features (VBS, HVCI) have less impact on AMD processors than Intel's. Besides, this issue is from months before Windows 11 was even speculated about, showing up in dev builds for Windows 10.
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#18
Darmok N Jalad
I’m really looking forward to Adler Lake reviews…on both Windows 10 and Windows 11. We’re going to see just how much had to be changed in software to hit performance claims, and it’s not the first time Intel’s “help” with software results in performance degradation when genuineIntel is not detected. It could quite possibly be a short-term marketing game. Early reviews will show Adler Lake looking significantly better than Ryzen on the latest and greatest Windows 11. A post-review patch from MS will come about and fix some of the glaring deficits, and only the enthusiast will know any better. Just needs to look good enough for investors to be happy and a line of commercials to air. MS gets the marketing might of Intel selling PCs with Windows 11. I can even see it being something like “only Intel 12 series CPUs are designed for Windows 11.” It all sounds like conspiracy until you look at history.
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#19
Tomorrow
As Intel is about to release Alder Lake that requires special scheduler under Win11 (that Microsoft happily obliged to build) AMD magicly loses on L3 performance before they are about to nearly double the L3 on their models.

Yeah totally no conspiracy or preferential treatmeant from Microsoft here...
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#20
ZoneDymo
and this is...somehow....a suprise?
not...something they noticed....when making this...revolutinary new OS?

not something they could have adressed when...making...it?
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#21
jesdals
Ah that explaine the recent leaked Intel benchmarks. They where all done in windows 11.......
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#22
ManofGod
Honestly, this means I am going to wipe my only install of Windows 11, which is lightly used, anyways. (I have no other installations of Windows.) I will go ahead back to Windows 10 and continue using my Ubuntu 20.04.3 installs as my daily drivers.
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#23
Turmania
Pretty sureit will be fixed soon. Dont know why many jumps into conclusion microsoft prefers Intel. Their xbox system in practically all AMD since their existence.
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#24
ManofGod
TurmaniaPretty sureit will be fixed soon. Dont know why many jumps into conclusion microsoft prefers Intel. Their xbox system in practically all AMD since their existence.
Because of recent history and commonsense because, even if I am wrong, it is not that much of a leap. The fact that their XBox Systems have AMD does not stop Microsoft from being buddy buddy with Intel, nonetheless.
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#25
seth1911
With 11 Intel is again the King with Single Chip Design against AMD with MCM :laugh:
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