Intel publishes first microcode update to address Raptor Lake stability issue, BIOSes now available

After a string of financial woes and stability issues with its Raptor Lake chips, Intel could have had some good news on Friday. And this week, they're delivering just that, releasing the first version of a long-awaited microcode fix for desktop Raptor Lake processors, as well as the first detailed explanation of the underlying issue.

The new microcode release, version 0x129, is Intel's first attempt to address the overvoltage issue that has apparently been the cause of performance degradation in Raptor Lake processors for the past year and a half. Intel has been investigating the issue all year, and after a slow start, has started making more significant progress in recent weeks, identifying what it calls an “overvoltage” issue in high-TDP desktop Raptor Lake (13^y and 14^y Generation Core) chips. Back in late July, the company was microcode fix release scheduled for mid-August To fix (or rather prevent) the degradation issue, and just before that deadline, Intel started sending microcode to its motherboard manufacturing partners.

However, even with this new microcode, Intel has not solved the stability issue. Intel is still investigating whether it can improve the stability of already degraded processors, and the overall tone of Intel’s announcement is very much like a beta software fix – Intel will not be sending this particular version of the microcode for distribution via operating system updates, for example. So even if this microcode successfully stops the ongoing degradation, it appears that Intel has not closed the book on the issue entirely, and that the company is apparently working on a fix suitable for a wider release.

Limit at 1.55V: High voltage produces high voltage

So what does microcode update 0x129 do? In short, it limits the voltage of the affected desktop Raptor Lake chips to a still-high (but in-spec) 1.55V. As noted in previous Intel announcements, the cause of the issue appears to be excessive voltages, so limiting voltages to what Intel has determined to be the proper limit should prevent future damage to the chips.

Letter from the company to the community also describes for the first time what exactly is going on under the hood of degraded chips. Those chips that had already succumbed to the problem due to repeated voltage spikes had deteriorated in such a way that the minimum voltage required to operate the chip – Vmin – exceeded Intel’s original specifications. As a result, these chips no longer receive enough voltage for work.

Experienced overclockers will no doubt find this a familiar story, as it’s one of the ways in which overclocked CPUs tend to get worse over time. In these cases — as seems to be the case with Raptor Lake — more voltage is required to keep the chip stable, especially in workloads where the chip’s voltage is already sagging.

And while all signs point to this degradation being irreversible (and plenty of RMAs in Intel's future), there is a silver lining. If Intel's analysis is correct that degraded Raptor Lake chips can still run fine with higher Vmin, there is a chance that at least some of these chips can be salvaged and returned to stability.

This “Vmin shift,” as Intel calls it, is the next target of the company’s investigation. According to the company’s letter, they intend to provide updates by “late August.”

Meanwhile, Intel's motherboard partners have already begun releasing BIOSes with the new microcode, with ASUS and MSI even jumping the gun and sending out BIOSes before Intel had a chance to properly announce the microcode. Both vendors are releasing these as beta BIOSes, reflecting the general early nature of the microcode fix. While we expect most users will want to install this microcode as soon as possible to mitigate further damage to affected chips, it would be prudent to treat these beta BIOSes as such.

In that vein, as noted earlier, Intel is currently only distributing microcode 0x129 via BIOS updates. This microcode will not be coming to other systems via operating system updates. At this point, we still expect that distribution via OS updates will be the end of this fix, but Intel has not yet provided a timeline or other indication of when that might happen. So for PC enthusiasts at least, a BIOS update is the only way to get it for now.

Performance impact: usually zero, but not always

Finally, Intel's post also gives a little guidance on the performance impact of the new microcode, based on their internal testing. The company has previously indicated that they don't expect a significant impact on performance, and based on their extensive testing, that remains generally the case. However, there will be some workloads that will suffer from performance regression as a result.

So far, Intel has found a few workloads that show regressions. These include PugetBench GPU Effects Score and, on the gaming side of things, Hitman 3: Dartmoor. Otherwise, almost everything else Intel has tested, including common benchmarks like Cinebench and mainstream games, shows no performance regressions. So the overall result of the fix isn’t exactly a perfect recovery, but it also doesn’t cause widespread performance losses.

As for AnandTechwe'll be digging into this on our own test suite as time permits. We have Another processor is expected to launch next week.so there'll be plenty of work in the coming days. (Sorry, Gavin!)

Intel's full statement