Modder uses Claude AI to rewrite BIOS so they can boot unsupported 12 P-core Bartlett Lake CPU in Windows on a Z790 motherboard

April 4, 2026 admin

After getting an OEM-exclusive 12 P-core Bartlett Lake CPU to post on an Asus Z790-AYW OC Wi-Fi, modder ‘kryptonfly’ on the Overclock.net forums has finally managed to boot the same chip into Windows using the same motherboard. A thread on the Overclock.net forums shows the numerous hurdles kryptonfly had to overcome to get Bartlett Lake to boot into Windows, with screenshots to prove everything.

The process involved BIOS modding with the help of Claude AI and numerous trial-and-error runs. After successfully getting the chip to POST, the main issue Krytonfly had to overcome next was a memory initialization issue preventing the system from going beyond the initial POSTing stage to boot into Windows. To achieve this, Kryptonfly fooled the Z790 motherboard into thinking the Bartlett Lake CPU’s system agent and PCIe graphics were part of a 13th/14th Gen Raptor Lake CPU.

the ocn bartlett lake thread is astonishing.from asking mobo vendors for help to swapping microcodes and modifying bios, they kept pushing the post code from getting stuck at 55 all the way to 99 a2 and finally posted.intel official supports bartlett lake on specific… https://t.co/SjqvFh2WLA pic.twitter.com/QNUgClTmmMApril 3, 2026

There are still issues the modder has to work out, including a problem where the Bartlett Lake CPU fails to enter the BIOS, making BIOS tweaks impossible without swapping CPUs. Nonetheless, getting a Bartlett Lake chip to boot into Windows is a huge achievement and one step forward to making Bartlett Lake fully functional on mainstream LGA 1700 motherboards. Kryptonfly confirmed he is already looking at implementing the BIOS on more boards, including LGA 1700 socket versions of the Asus Apex and Encore.

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Bartlett Lake-S is one of Intel’s most unorthodox CPU lineups to date, featuring a flagship SKU that offers a 12 P-core design that clocks up to 5.9GHz. Although these chips are targeted at embedded and edge applications, the top-end 10-core and 12-core models have caught the attention of enthusiasts for their very unique high-core-count P-core-only configurations. None of Intel’s existing hybrid chips come with more than eight P-cores, including the Core i9-14900K and Core Ultra 9 285K.

Practically, there’s not much the 12-core Core 9 273QPE or 10-core Core 7 253QPE can achieve over their existing Raptor Lake counterparts, especially since Bartlett Lake lacks E-cores altogether. However, in niche latency-sensitive applications that take advantage of only 12 or 10 cores, these chips could potentially outperform a Core i9-14900K or an Ultra 9 285K. Again, though, this is a very niche window where Bartlett Lake-S could potentially outperform conventional Intel desktop CPUs.