An AI computing enthusiast has demonstrated Doom running on a custom CPU designed by GPT-5.6 Sol. Angel (@Angaisb_) shared a technical and visual feast with a video of classicDoom running within a pulsing schematic of the CPU, in the sandbox provided by theTuring Complete game environment. Clearly, this shows that GPT-5.6 Sol is capable of constructing a virtual computer system from the basics, and one that is accurate enough to boot and play a port of the originalDoom. The model dubbed its CPU design ‘Codex-R32.’
People asked for DOOM so here's DOOM running on GPT-5.6 Sol's custom CPU, it called it Codex-R32Truly insane that we can do stuff like this pic.twitter.com/aCIR8aYAlaAugust 23, 2026
Angel knows Doom is a hugely popular demo to show computing capabilities, despite it being quite a vintage nowadays (1993). So they must have thought it a good idea to show how far agentic coding has come with this tried and trusted ‘people asked forDoom’ metric. They were impressed by the results, concluding that it is “truly insane that we can do stuff like this.”
Despite the accomplishment, another rule of the internet is that there’s always someone who thinks you haven’t pushed far enough. So there were the inevitable remarks about having a shot at Crysis next. Likely grasping for a witty comeback, Angel asked their AI to whip up a response to the unsolicited stretch goal. It didn’t disappoint, suggesting they answer “Absolutely – I just need to build a GPU, add a few gigabytes of RAM, and make a schematic visible from orbit first.”
Indeed, Doom is a relative minnow compared toCrysis, though it still stretches the model and its performance in the sandbox is not what anyone would call playable. “The CPU is built from primitive logic components inside* Turing Complete*,” the Codex told Angel. “* Doomuses the C-based PureDOOM* port, compiled into native RV32IM machine code that runs directly on the custom Codex‑R32 CPU.”
Watching the video, you can see the live schematic of the custom CPU with a pulsing visualization of processor gates, registers, memory, ALUs, and other blocks within the Turing Complete computer-science education and puzzle game’s anything-goes sandbox mode. Live stats show the cycle counter, sim speed, memory/register values, and more.
Overall, with this demo, we have a neat visual demo of LLMs not just creating software, but also reinventing hardware at a capable enough level to pass the 'can it run Doom' test.
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Mark Tyson is a news editor at Tom's Hardware. He enjoys covering the full breadth of PC tech; from business and semiconductor design to products approaching the edge of reason.