Raptor Lake microcode limits Intel chips to a mere 1.55 volts to prevent CPU destruction

Intel has divulged more details on its Raptor Lake family of 13th and 14th Gen Core processor failures and the 0x129 microcode that's supposed to prevent further damage from occurring.

The chipmaker previously disclosed that the so-called instability issue plaguing many Raptor Lake chips stems from an elevated operating voltage set by the processor itself. Essentially, while relatively high voltage is crucial to maintaining stability at high clock speeds, there's a limit to how much a processor can tolerate. If voltage is set to a dangerously high value, it can permanently damage the processor, causing crashes at what should be stable frequencies if not fry the thing dead, as Intel customers have discovered.

Previously, it was unclear what Intel considered "elevated," but with a new advisory from Chipzilla now we finally have an answer: Anything above 1.55 volts.

In case you're wondering, 1.55 volts – which presumably only kicks in during single- and lightly threaded workloads – is high for a desktop CPU in 2024, let alone anything above that. For comparison, Intel's older 12th Gen CPUs based on Alder Lake tended to max out around 1.4 to maybe 1.45 volts. AMD's Ryzen 7000 CPUs are also in the same ballpark, and the latest Ryzen 9000 chips probably are, too.

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It's not entirely surprising that 13th and 14th Gen Core CPUs require this level of voltage to hit their maximum boost frequencies (again, on one or two cores), which are the highest for desktop processors. While AMD has only ever been able to hit 5.7 GHz, and Alder Lake capped out at 5.5 GHz; the fastest Raptor Lake CPUs range from 6 to 6.2 GHz.

It's not clear how high the operating voltage was getting before the introduction of the 0x129 microcode, but apparently 1.55v is in the sweet spot to prevent damage but still guarantee high clock speeds.

According to Intel's internal testing, performance largely hasn't changed for Raptor Lake CPUs with the new microcode; the x86 giant warned there was one application, the Dartmoor mission in video game Hitman 3, where it saw some performance hit. "System performance is dependent on configuration and several other factors," the corp noted.

Hardware benchmarkers will likely have the final word on that.

Overclocking is still an option for K-class chip owners, but given the circumstances, maybe pushing Raptor Lake processors isn't such a great idea.

Intel also says that affected processors that aren't completely dead have a higher minimum operating voltage across multiple cores. We've asked Intel for further details on the implications of this.

Motherboard vendors begin to supply BIOS updates

This announcement comes just after Intel's motherboard partners began to release BIOS patches containing the new microcode for their LGA 1700 motherboards. MSI has pledged to update all of its 600 and 700 series motherboards by the end of the month, and it has already started doing so by releasing beta BIOSes for its highest-end Z790 boards. ASRock meanwhile silently issued updates for all of its 700 series motherboards.

ASUS says it will begin releasing new BIOSes next week, while in a statement to The Register, Gigabyte has merely committed itself to finish patching its motherboards by the second week of September. Dell told us: "Dell recently received the Intel BIOS update and our engineers are working quickly to validate it with our systems. We expect to make validated updates available to our customers next week."

The picture isn't clear for how BIOS updates will work for owners of OEM pre-builts, however. The Register reached out to HP, too, for comment on how they'll handle updating their 13th and 14th Gen desktops, and we haven't heard back yet.

Meanwhile, Intel has postponed its Innovation event, scheduled for mid-September. ®

Sidenote

Intel rival AMD issued two security advisories this week regarding some interesting-but-not-too-scary flaws in its chips. One has been dubbed Sinkclose, aka CVE-2023-31315, and allows miscreants who have gone as far as compromising a machine's kernel, at ring-0, to then run code within System Management Mode, and thus infect the computer in a way that may be hard or impossible to remove. See AMD's write-up for details.

Another advisory, for CVE-2024-21978, CVE-2024-21980, and CVE-2023-31355, warns that malicious hypervisors can access guest memory that was supposed to be protected by AMD's Secure Encrypted Virtualization. Again, see the write-up for the next steps.