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kvdivergence

confirmedPython · llama.cppInference & servingJuly 7, 2026

the question

Does quantizing the KV cache change the greedy output?

what came out

Yes -- q8_0 KV changes the generated text on 83% of prompts, q4_0 on 100% (often from the start), with flash attention held constant. KV precision alone changes what the model says: 8-bit KV is not lossless at the token level. Controlled, pre-registered, code-reviewed.

method & receipts

  • Result: confirmed
  • Pre-registered the prediction was written down and committed before the run.
  • Reproducible one script re-runs the whole thing from scratch.
  • Independently reviewed an adversarial review pass, kept in the repo.
  • Machine-readable claims every reported number, in a checkable file.
  • Tested — a correctness/benchmark suite ships alongside the code.

→ read the code and re-run it

github.com/v-code01/kvdivergence