Owners of Intel's 13th and 14th Gen Core processors may need to stick to the chip giant's official power limits in order to safely use their CPUs.

A new version of Intel's microcode limits the voltage applied to the Raptor Lake family of 13th and 14th Gen desktop processors to 1.55 volts, which is supposed to prevent the components from frying themselves. But on one such motherboard, Gigabyte's high-end Z790 Aorus Master X, that 1.55 volt limit only works if users stick to the official "Intel Default Settings" power limits.

Overclocking expert Buildzoid
demonstrated his Raptor Lake Core i9-14900K, installed in a Z790 Aorus Master X motherboard, spiking to 1.5616 volts just 45 seconds after booting into Windows; it later peaked to 1.5792 volts after running some benchmarks.

While that's only a few tens of millivolts beyond the 1.55 volt limit, it can be the difference between safe and dangerous voltage levels that crash or damage the processor.

The microcode patch is currently being distributed by Intel's motherboard partners via new BIOSes, which have been released for many 600 and 700 series boards thus far.

Intel sets official power specifications for its CPUs, termed "Intel Default Settings," but motherboard vendors can also offer their own power settings, which often boost power and performance higher. Enabling these performance-boosting power limits has been desirable for Intel users for years, and on many motherboards are actually the default, rather than Intel's official settings.

Although these options technically count as overclocking and only work on unlocked K-class CPUs, they've been considered safe to enable since they don't govern voltage, only wattage and amperage.

However, at least on this one Gigabyte motherboard, it appears that ditching Intel's official power settings disabled the 1.55 volt limit that's intended to keep Raptor Lake CPUs unharmed. When Intel initially described the microcode and its voltage limiting feature, it sounded like it would be enabled unless users explicitly wanted to disable it for overclocking.

"This latest microcode update (0x129) will not prevent users from overclocking if they so choose," the Xeon giant wrote on Friday. "Users can disable the eTVB setting in their BIOS if they wish to push above the 1.55V threshold."

Enabling an Intel Default Settings power profile has never been mentioned as a key requirement for enabling the 1.55 volt limit, The Register understands. We've reached out to Intel and Gigabyte for comment on why this behavior emerged - and who's to blame - but so far we've not received a response.

Thankfully for Raptor Lake users, Intel's motherboard partners are now required to use Intel's power limits by default, so the only users affected would be those who choose to switch away from the Intel Default Settings. ®

https://www.theregister.com//2024/08/12/raptor_lake_cpu_microcode_patch/