How much VRAM do you need for a 300B–480B model?

Short answer: about 282.2 GB at Q4_K_M, the usual quant for local use. Below: every quant, longer contexts, the cheapest hardware that fits, and every 300B–480B open model we track.

Q4_K_M

282.2 GB 244.6 GB weights

Q8_0

493.9 GB 428.6 GB weights

FP16

928.8 GB 806.8 GB weights

Worked out for Qwen3.5-397B-A17B (403.4B parameters, from the Hugging Face API). Formula: weights × 1.15 + 1 GB at a ~4k context (how we calculate).

No single consumer GPU we track fits it at Q4. Cheapest Mac or mini PC: Mac Studio M5 Ultra 512GB ($22,299).

Cheapest hardware for each quant

Only devices with a sourced price. GPUs at list price (MSRP); street prices may be higher.

No single consumer GPU we track holds a 300B–480B model at Q4. Your options: two or more GPUs (see the ready-made builds or the planner), a large unified-memory machine (see the best Mac for local LLMs), or a smaller quant with lower quality.

Memory by context length

Each extra token of context adds to the KV cache. Numbers for Qwen3.5-397B-A17B, from its published config; a Q8 KV cache halves the cache part.

Hardware that runs it

300B–480B models we track

Have a different amount of memory? Try the VRAM calculator or see best LLMs by VRAM size.

Other sizes: 1B–2B · 2B–3B · 4B–6B · 7B–8B · 12B–14B · 16B–21B · 24B–27B · 30B–32B · 40B–50B · 70B · 120B · 200B–300B · 500B–800B · 1T+ · All sizes · Ollama VRAM by tag · GGUF sizes by quant