ISTA quantizes DeepSeek-V4.1-Flash to 2 bits with zero benchmark loss, runs on one 12GB GPU

Loginhe · reddit · 2026-10-24

ISTA-DASLab released GSQ+RCO quantized GGUFs of DeepSeek-V4.1-Flash-1017, a 763.2B-parameter sparse MoE (6/384 active experts, 1M context), at 1.75–2.25 bpw. Three builds (120.7–155.2GB backbones) plus one shared 110.6GB Engram file run on a single 12GB GPU via Strata with an OpenAI-compatible endpoint (llama.cpp not yet supported). GSQ post-training scalar quantization nearly closes the gap to vector quantization, while RCO enforces exact bit budgets via gradient descent with separate ladders for dense and expert tensors. At 2.00 bpw the model exactly matches the base on AIME25, GPQA-Diamond and LiveCodeBench v6; IQ1M retains 98.7%.

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