Feed: AnandTech
Feed Link: https://www.anandtech.com
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Title: Intel Addresses Desktop Raptor Lake Instability Issues: Faults
Excessive Voltage from Microcode, Fix Coming in August

Date: Mon, 22 Jul 2024 19:00:00 EDT
Link: https://www.anandtech.com/show/21484/intel-ra...

In what started last year as a handful of reports about instability with
Intel's Raptor Lake desktop chips has, over the last several months, grown
into a much larger saga. Facing their biggest client chip instability
impediment in decades, Intel has been under increasing pressure to figure out
the root cause of the issue and fix it, as claims of damaged chips have
stacked up and rumors have swirled amidst the silence from Intel. But, at
long last, it looks like Intel's latest saga is about to reach its end, as
today the company has announced that they've found the cause of the issue,
and will be rolling out a microcode fix next month to resolve it.

Officially, Intel has been working to identify the cause of desktop Raptor
Lake's instability issues since at least February of this year, if not
sooner. In the interim they have discovered a couple of correlating factors -
telling motherboard vendors to stop using ridiculous power settings for their
out-of-the-box configurations, and finding a voltage-related bug in Enhanced
Thermal Velocity Boost (eTVB) - but neither factor was the smoking gun that
set all of this into motion. All of which had left Intel to continue
searching for the root cause in private, and lots of awkward silence to fill
the gaps in the public.

But it looks like Intel's search has finally come to an end - even if Intel
isn't putting the smoking gun on public display quite yet. According to a
fresh update posted to the company's community website, Intel has determined
the root cause at last, and has a fix in the works.

Per the company's announcement, Intel has tracked down the cause of the
instability issue to "elevated operating voltages", that at its heart, stems
from a flawed algorithm in Intel's microcode that requested the wrong
voltage. Consequently, Intel will be able to resolve the issue through a new
microcode update, which pending validation, is expected to be released in the
middle of August.

Based on extensive analysis of Intel Core 13th/14th Gen desktop processors
returned to us due to instability issues, we have determined that elevated
operating voltage is causing instability issues in some 13th/14th Gen desktop
processors. Our analysis of returned processors confirms that the elevated
operating voltage is stemming from a microcode algorithm resulting in
incorrect voltage requests to the processor.

Intel is delivering a microcode patch which addresses the root cause of
exposure to elevated voltages. We are continuing validation to ensure that
scenarios of instability reported to Intel regarding its Core 13th/14th Gen
desktop processors are addressed. Intel is currently targeting mid-August for
patch release to partners following full validation.

Intel is committed to making this right with our customers, and we continue
asking any customers currently experiencing instability issues on their Intel
Core 13th/14th Gen desktop processors reach out to Intel Customer Support for
further assistance.
-Intel Community Post

And while there's nothing good for Intel about Raptor Lake's instability
issues or the need to fix them, that the problem can be ascribed to (or at
least fixed by) microcode is about the best possible outcome the company
could hope for. Across the full spectrum of potential causes, microcode is
the easiest to fix at scale - microcode updates are already distributed
through OS updates, and all chips of a given stepping (millions in all) run
the same microcode. Even a motherboard BIOS-related issue would be much
harder to fix given the vast number of different boards out there, never mind
a true hardware flaw that would require Intel to replace even more chips than
they already have.

Still, we'd also be remiss if we didn't note that microcode is regularly used
to paper over issues further down in the processor, as we've most famously
seen with the Meltdown/Spectre fixes several years ago. So while Intel is
publicly attributing the issue to microcode bugs, there are several more
layers to the onion that is modern CPUs that could be playing a part. In that
respect, a microcode fix grants the least amount of insight into the bug and
the performance implications about its fix, since microcode can be used to
mitigate so many different issues.

But for now, Intel's focus is on communicating that they have fix and
establishing a timeline for distributing it. The matter has certainly caused
them a lot of consternation over the last year, and it will continue to do so
for at least another month.

In the meantime, we've reached out to our Intel contacts to see if the
company will be publishing additional details about the voltage bug and its
fix. "Elevated operating voltages" is not a very satisfying answer on its
own, and given the unprecedented nature of the issue, we're hoping that Intel
will be able to share additional details as to what's going on, and how Intel
will be preventing it in the future.

Intel Also Confirms a Via Oxidation Manufacturing Issue Affected Early Raptor
Lake Chips

Tangential to this news, Intel has also made a couple of other statements
regarding chip instability to the press and public over the last 48 hours
that also warrant some attention.

First and foremost, leading up to Intel's official root cause analysis of the
desktop Raptor Lake instability issues, one possibility that couldn't be
written off at the time was that the root cause of the issue was a hardware
flaw of some kind. And while the answer to that turned out to be "no," there
is a rather important "but" in there, as well.

As it turns out, Intel did have an early manufacturing flaw in the enhanced
version of the Intel 7 process node used to build Raptor Lake. According to a
post made by Intel to Reddit this afternoon, a "via Oxidation manufacturing
issue" was addressed in 2023. However, despite the suspicious timing,
according to Intel this is separate from the microcode issue driving
instability issues with Raptor Lake desktop processors up to today.

Short answer: We can confirm there was a via Oxidation manufacturing issue
(addressed back in 2023) but it is not related to the instability issue.

Long answer: We can confirm that the via Oxidation manufacturing issue
affected some early Intel Core 13th Gen desktop processors. However, the
issue was root caused and addressed with manufacturing improvements and
screens in 2023. We have also looked at it from the instability reports on
Intel Core 13th Gen desktop processors and the analysis to-date has
determined that only a small number of instability reports can be connected
to the manufacturing issue.

For the Instability issue, we are delivering a microcode patch which
addresses exposure to elevated voltages which is a key element of the
Instability issue. We are currently validating the microcode patch to ensure
the instability issues for 13th/14th Gen are addressed.
-Intel Reddit Post

Ultimately, Intel says that they caught the issue early-on, and that only a
small number of Raptor Lake were affected by the via oxidation manufacturing
flaw. Which is hardly going to come as a comfort to Raptor Lake owners who
are already worried about the instability issue, but if nothing else, it's
helpful that the issue is being publicly documented. Typically, these sorts
of early teething issues go unmentioned, as even in the best of scenarios,
some chips inevitably fail prematurely.

Unfortunately, Intel's revelation here doesn't offer any further details on
what the issue is, or how it manifests itself beyond further instability.
Though at the end of the day, as with the microcode voltage issue, the fix
for any affected chips will be to RMA them with Intel to get a replacement.

Laptops Not Affected by Raptor Lake Microcode Issue

Finally, ahead of the previous two statements, Intel also released a
statement to Digital Trends and a few other tech websites over the weekend,
in response to accusations that Intel's 13th generation Core mobile CPUs were
also impacted by what we now know to be the microcode flaw. In the statement,
Intel refuted those claims, stating that laptop chips were not suffering from
the same instability issue.

Intel is aware of a small number of instability reports on Intel Core
13th/14th Gen mobile processors. Based on our in-depth analysis of the
reported Intel Core 13th/14th Gen desktop processor instability issues, Intel
has determined that mobile products are not exposed to the same issue. The
symptoms being reported on 13th/14th Gen mobile systems - including system
hangs and crashes - are common symptoms stemming from a broad range of
potential software and hardware issues. As always, if users are experiencing
issues with their Intel-powered laptops we encourage them to reach out to the
system manufacturer for further assistance.
-Intel Rep to Digital Trends

Instead, Intel attributed any laptop instability issues to typical hardware
and software issues - essentially claiming that they weren't experiencing
elevated instability issues. Whether this statement accounts for the via
oxidation manufacturing issue is unclear (in large part because not all 13th
Gen Core Mobile parts are Raptor Lake), but this is consistent with Intel's
statements from earlier this year, which have always explicitly cited the
instability issues as desktop issues.

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