Quantize, Qualify, Rerank: A Recipe for Compressing LLMs Without Losing Quality

Thamme Gowda


Abstract
Compressing large language models lowers serving cost, but a single automatic metric may miss quality loss. For the WMT26 Model Compression constrained track, we compress ‘google/gemma-3-12b-it‘ (24.4 GB in bf16) for three translation directions on one H100. Paired bootstrap analysis exposes metric disagreement on 4-bit quantization; guided by WMT24 human meta-evaluation, we use MetricX24-XXL as primary and CometKiwi-XXL as a cross-check. Removing the unused vision stack and non-task vocabulary and using int8 weights or fp8 activations causes no measurable loss, whereas int4 leaves a small residual. QLoRA healing overfits its calibration domain. A cheap Cometoid best-of-4 reranker at ‘T=0.3‘ improves both the 8-bit and 4-bit systems under held-out CometKiwi-XXL and reference-based MetricX24-XXL. Both surpass greedy bf16 on CometKiwi-XXL; the 8-bit system also surpasses it on MetricX24-XXL, while the 4-bit system nearly matches it.
Anthology ID:
2026.wmt-main.136
Volume:
Proceedings of the Eleventh Conference on Machine Translation
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Barry Haddow, Tom Kocmi, Philipp Koehn, Christof Monz
Venues:
WMT | WS
SIG:
SIGMT
Publisher:
Association for Computational Linguistics
Note:
Pages:
1991–1998
Language:
URL:
https://aclanthology.org/2026.wmt-main.136/
DOI:
Bibkey:
Cite (ACL):
Thamme Gowda. 2026. Quantize, Qualify, Rerank: A Recipe for Compressing LLMs Without Losing Quality. In Proceedings of the Eleventh Conference on Machine Translation, pages 1991–1998, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
Quantize, Qualify, Rerank: A Recipe for Compressing LLMs Without Losing Quality (Gowda, WMT 2026)
Copy Citation:
PDF:
https://aclanthology.org/2026.wmt-main.136.pdf