JetBrains Mellum2.1 model's recommended download size is 8.07 GB, analysis finds

An analysis of JetBrains' Mellum2.1-12B coding model reveals its recommended Q4_K_M quantization file is 8.07 GB. The model uses a mixture-of-experts architecture with 12B total weights but only 2.5B active per token, allowing it to run on hardware that couldn't support a dense 12B model. According to Hugging Face data from October 2026, the smallest available quantization is 7.03 GB, but it requires recent software builds. JetBrains' own benchmarks show the model excels at single-shot code generation but trails a smaller dense model on multi-step agentic tasks. The analysis advises users to verify system memory against actual file sizes plus runtime overhead rather than parameter counts.