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what is pxq_llama fr?

poisonxa16/pxq_llama — explained in plain English

Analysis updated 2026-05-18

17C++Audience · developerComplexity · 5/5Setup · hard

tl;dr

pxq_llama is a llama.cpp fork with new low-bit PXQ quantization and fused CUDA kernels that let large mixture-of-experts models run fast on old, cheap Pascal and Volta GPUs.

vibe map

mindmap
  root((pxq_llama))
    What it does
      Runs MoE LLMs on old GPUs
      PXQ low-bit quantization
      Fused CUDA kernels
    Tech stack
      C++
      CUDA
      llama.cpp fork
    Hardware
      Pascal
      Volta
      Salvaged Teslas
    Use cases
      Single-card 35B
      Multi-card 120B MoE
      Benchmarking vs upstream

Code map

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filefunction / class

what do people make with this?

VIBE 1

Run a 35B parameter mixture-of-experts model on a single secondhand 12 to 16GB GPU instead of needing top-tier hardware.

VIBE 2

Speed up mixture-of-experts inference on older Pascal or Volta GPUs like the P100, V100, or 1080 Ti.

VIBE 3

Quantize a model's expert layers down to 2, 3, or 4 bits per value using the PXQ format to fit more model in less GPU memory.

VIBE 4

Spread a large 120B-class model across a stack of older GPUs, or partially offload it to system RAM.

what's the stack?

C++CUDAllama.cpp

how it stacks up fr

poisonxa16/pxq_llamaeversinc33/karyogunnerenchant32/team-fortress-2-dominate-every-match
Stars171717
LanguageC++C++C++
Setup difficultyhardhardeasy
Complexity5/55/51/5
Audiencedeveloperdevelopergeneral

Figures from each repo's GitHub metadata at analysis time.

how do i run it?

Difficulty · hard time til it works · 1h+

Requires a CUDA 12.x toolchain and familiarity with local LLM inference tuning, not beginner friendly.

No license information was stated in the README.

in plain english

pxq_llama is a fork of ik_llama.cpp, itself a variant of the popular llama.cpp project for running large language models locally. This project focuses specifically on making older, cheaper NVIDIA GPUs, the kind sold secondhand as surplus rather than current top of the line cards, useful for running large modern AI models that would normally need much more expensive hardware. The project does this in two parts. First, it fixes and speeds up the underlying engine so that any mixture of experts model, a type of large model that only activates part of itself for each request, runs faster on older Pascal and Volta generation GPUs, whether on a single card, spread across several cards, or partly offloaded to a computer's regular memory. Second, it introduces its own family of compression formats called PXQ, which shrink a model's expert layers down to two, three, or four bits per value instead of the usual higher precision, paired with custom CUDA code tuned for that older hardware. Together these let a 35 billion parameter model run on a single graphics card with only twelve to sixteen gigabytes of memory, something around 150 dollars can buy secondhand, and let much larger models in the 120 billion parameter range run across a stack of older cards. The README includes detailed, reproducible benchmark comparisons against the original ik_llama.cpp project, measuring both how fast the model processes an initial prompt and how fast it generates new text afterward, on specific card models like the P100, V100, and 1080 Ti. Recent updates describe renaming its quantization tiers for clarity, fixing a bug in an experimental kernel, and adding new optional environment variables that trade a small amount of numerical exactness for a large speed increase on certain older cards. Building the project requires a CUDA toolchain and is aimed squarely at people already comfortable running large language models locally and tuning GPU inference performance, rather than newcomers.

prompts (copy fr)

prompt 1
Help me build pxq_llama with CUDA and quantize a model to PXQ4 for my old P100 GPU.
prompt 2
Explain the difference between pxq_llama's PXQ2, PXQ3, and PXQ4 quantization tiers.
prompt 3
Show me the recommended command line settings in docs/COOKBOOK.md for running a model on a 1080 Ti.
prompt 4
Walk me through what PXA_FUSE_DELTANET and PXA_G2_ADDFUSE do and when I should enable them.

Frequently asked questions

what is pxq_llama fr?

pxq_llama is a llama.cpp fork with new low-bit PXQ quantization and fused CUDA kernels that let large mixture-of-experts models run fast on old, cheap Pascal and Volta GPUs.

What language is pxq_llama written in?

Mainly C++. The stack also includes C++, CUDA, llama.cpp.

What license does pxq_llama use?

No license information was stated in the README.

How hard is pxq_llama to set up?

Setup difficulty is rated hard, with roughly 1h+ to a first successful run.

Who is pxq_llama for?

Mainly developer.

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