A comprehensive technical guide on setting up a high-performance local large language model environment for agentic coding tasks. The author demonstrates how to run a quantized Qwen3.5-27B model on a remote RTX 4090 workstation and access it from a MacBook using Tailscale, integrating the setup with OpenCode and Codex.
Key topics include:
* Step-by-step llama.cpp build configuration for CUDA support.
* Using Tailscale to create a secure network between client and GPU machine.
* Optimizing VRAM usage through specific quantization (UD-Q4_K_XL) and context size management.
* Implementing a corrected chat template to prevent tool-calling errors in agentic workflows.
* Performance insights regarding hybrid architectures and KV cache precision.
This article details benchmarks for Unsloth Dynamic GGUFs of the Qwen3.5 model, including analysis of perplexity, KL divergence, and MXFP4. It covers performance across different bit widths and quant types, highlighting the impact of Imatrix and the limitations of certain quantization approaches. Full benchmark data is also provided.