Quick Answer

A Worcester local-LLM build should lead with a high-VRAM NVIDIA GPU and ample system RAM. An RTX 4070 (12GB) runs mid-sized quantised models; an RTX 4080 (16GB) or 4090 (24GB) runs larger ones faster. Add 32GB to 64GB RAM and a fast NVMe SSD, with the tower around R28,000 to R55,000. VRAM is fixed on a card, so choosing enough now matters since gaining more later means replacing the GPU. A 1TB or larger NVMe SSD stores multiple large models and loads them quickly.

Matching Hardware To Models

VRAM is the key spec: 12GB suits quantised 7B to 13B models, 16GB extends the range, and 24GB runs larger models with headroom. The GPU's speed determines tokens per second, so a stronger card responds faster. NVIDIA remains the default because the popular local LLM runtimes are built around its CUDA support.

Rounding Out The System

System RAM of 32GB to 64GB serves as overflow for models that exceed VRAM, adding flexibility at a speed cost. A 1TB or larger NVMe SSD stores multiple large models and loads them quickly. A PSU sized to the GPU keeps sustained inference stable, while a capable mid-range CPU is enough to support the GPU-led workload.

FAQ

What is a good starter GPU for local LLMs?

A 12GB card like an RTX 4070 runs many capable quantised models and is a sensible entry. Step up to 16GB or 24GB when you want larger models or more speed.

How much RAM should I pair with the GPU?

32GB is comfortable for general use, while 64GB helps load larger models that overflow VRAM. The GPU's memory still does the fast inference work.

Can I upgrade VRAM later?

VRAM is fixed on a graphics card, so to gain more you replace the GPU. That makes choosing enough VRAM up front important for future model sizes.

Buy the VRAM your target models need, with room to grow. Pick a 12GB to 24GB NVIDIA GPU, pair 32GB to 64GB RAM and a fast NVMe SSD, and size the PSU to the card before ordering.