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
Add your own comment

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

#76
zlobby
windwhirlEh, it's already fixed in Dev, so MS will probably just backport it to RTM
It begs the question how did this slip during internal testing? Oh, wait!
Posted on Reply
#77
Arkz
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.
Since Xbox one. So only 2 console generations. 360 was an IBM PowerPC CPU and OG Box was a Pentium 3/Celeron hybrid.

Either way it will be fixed, they'll probably update the Xbox Series kernel to W11 at some point too so obviously they'd need it fixed in that.
Posted on Reply
#78
billEST
windwhirlAh, I posted that in another thread. Here you go:

www.tomshardware.com/news/windows-11-security-gaming-application-performance-benchmarks

Tom's Hardware's tested VBS on and off on Intel's 10700K and 11700K and AMD's 3800X and 5800X. Mind you, this are merely tests on VBS impact alone, it's got nothing on whatever is going on with the L3 cache issue.

The 15% impact is an AMD's estimated measure on select games
there is a fail in the test they use Z490 for both 10 and 11 g .. or there is real difference in perf between Z490 and Z590 ...
Posted on Reply
#80
windwhirl
billESTthere is a fail in the test they use Z490 for both 10 and 11 g .. or there is real difference in perf between Z490 and Z590 ...
No, Z490 supports both 10 and 11th gen Intel CPUs
zlobbyIt begs the question how did this slip during internal testing? Oh, wait!
Yeah, it's strange as hell.
Posted on Reply
#81
R-T-B
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 AIDA64 cache benchmark. It shows there bad in the L3 cache section.

I have not noticed it either but I doubt AMD would claim this were it not true.
TheoneandonlyMrKLikely to do with VMR (acronym might be VmS or something, no VBS read the thread) ie fully virtualized OS security.
It's not even on in fresh installs, so no.
TheoneandonlyMrKThere were reports it'll affect ALL CPUs as much as 25%.
Not to my knowledge. No benchable figures like AMD.
Posted on Reply
#82
AlwaysHope
MakaveliYou are a brave soul I never touch a new OS for at least 6 months.
+1 here too! :)
Posted on Reply
#83
Minus Infinity
AlwaysHope+1 here too! :)
Make it 12 months or more in this case.
Posted on Reply
#84
Lionheart
Darmok N JaladI’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.
I like how you can see the domino effect & past the obvious BS. :toast:
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.
It's not about preferring Intel, it's just obvious business practices, annoying dodgy ones at that, Intel has more mindshare advertisement muscle, gotta sell that "new" Windows 11 & most PC's out there are Intel.
phanbueyI mean AMD knows about it... MS knows about it...

Reality is MS loves AMD (Xbox is amd based), and is familiar with AMD architectures... doubtful this will be around for very long.
I'd say couple months at least, gotta make those Windows 11 sales with Intel based Machines, it's scummy & brilliant at the same time. lol
Posted on Reply
#85
AlwaysHope
Minus InfinityMake it 12 months or more in this case.
That is most certainly not out of the question either.

Having said that though, I am looking at a platform upgrade in the next couple months, hardware wise at least.
Posted on Reply
#86
Mysteoa
LionheartI'd say couple months at least, gotta make those Windows 11 sales with Intel based Machines, it's scummy & brilliant at the same time. lol
It's already fix in Dev build.
Posted on Reply
#87
R-T-B
MysteoaIt's already fix in Dev build.
That is what I just migrated to temporarily.

Is indeed fixed.
Posted on Reply
#88
DemonicRyzen666
Not a surprise to me. Similar thing happened going from Core2duo to Nahalem i7 on XP/Vista 64 OS. to windows 7 OS. 15% up lift for Intel on Nehalem i7 chips.
All down to scheduler fixes.
Posted on Reply
#89
Patriot
R-T-BThat is what I just migrated to temporarily.

Is indeed fixed.
Now if its not pushed to public before alders lake benchmarks is where this returns to a conspiracy.
Posted on Reply
#90
eidairaman1
The Exiled Airman
glsnquestion: If I do update to w11, I should also resetup all the apps/configs?
Yes
Posted on Reply
#91
TheDeeGee
Judging by the comments noone read the article all the way to the end.

Maybe change the headline to: "Windows 11 fix underway for AMD 15% performance loss bug."
Posted on Reply
#92
phanbuey
exactly - fix will be out before Alderlake even hits the market.
Posted on Reply
#93
mama
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.
What are your specs?
Posted on Reply
#94
Bomby569
zlobbyIt begs the question how did this slip during internal testing? Oh, wait!
or what more has to be discovered and never been tested
Posted on Reply
#95
Melvis
ok cool so ANY leaked benchmarks of up and coming hardware is now complete and utter rubbish/BS, awesome! thanks for clearing all that up for us!

I can see it now......terrible, bad, inaccurate reviews will pop up all over the net in amonths time where A is running on 11 but B is not etc etc.
Posted on Reply
#96
zlobby
Bomby569or what more has to be discovered and never been tested
Yes. It was meant as a sarcasm. It was implying that Microsoft don't do any internal testing at all, even for the most critical parts.

Even if they did, someone should really lose their job for missing stuff like this.
Melvisok cool so ANY leaked benchmarks of up and coming hardware is now complete and utter rubbish/BS, awesome! thanks for clearing all that up for us!

I can see it now......terrible, bad, inaccurate reviews will pop up all over the net in amonths time where A is running on 11 but B is not etc etc.
But all the verdics will be 'intel takes back the crown', 'intel rullz, amd sucks', etc. Many people will cream their underwear and rush to the stores to get the latest and greatest from intel.
Posted on Reply
#97
Wirko
I'm amazed to hear that cache latency can be controlled by software in any way.
Posted on Reply
#98
zlobby
WirkoI'm amazed to hear that cache latency can be controlled by software in any way.
Actually, many, many things happen before a processor 'executes' an instruction. And even then there are sets of internal (to the processor) things that take place.
More so, with all the branching, speculative executions and other kinky stuff, the entire system becomes really volatile from users' perspective.
Posted on Reply
#99
Vayra86
This summarizes the upgrade quite well I think. Its really something you don't need and might never make use of, is it? But marketing says its better. Not sure if its louder... :)

Posted on Reply
#100
zlobby
Vayra86This summarizes the upgrade quite well I think. Its really something you don't need and might never make use of, is it? But marketing says its better. Not sure if its louder... :)

:roll: :roll: :roll::roll:
Spot on, bruv!
Posted on Reply
Add your own comment