LLM VRAM Checker

Running Qwen2.5 72B locally

Alibaba · 72B parameters · released 2024-09

Qwen2.5 at near-frontier scale. Comparable memory class to Llama 3.3 70B — around 43 GB at Q4.

Q4 — 4-bit quantized

≈ 41.8 GB

weights only, plus 2 GB context headroom rule

Q8 — 8-bit quantized

≈ 76.3 GB

weights only, plus 2 GB context headroom rule

Verdicts by hardware

HardwareUsableQ4 (41.8 GB)Q8 (76.3 GB)
RTX 4090 (24 GB)24 GBToo bigToo big
RTX 3090 (24 GB)24 GBToo bigToo big
RTX 4070 Ti SUPER (16 GB)16 GBToo bigToo big
RTX 4060 Ti (16 GB)16 GBToo bigToo big
RTX 3060 (12 GB)12 GBToo bigToo big
RTX 4060 (8 GB)8 GBToo bigToo big
MacBook Air M2 (8 GB unified)5.6 GBToo bigToo big
MacBook Pro M4 Pro (48 GB unified)33.6 GBToo bigToo big
Mac Studio M2 Max (64 GB unified)44.8 GBRuns wellToo big
CPU only (32 GB system RAM)25.6 GBToo bigToo big
CPU only (16 GB system RAM)12.8 GBToo bigToo big

Notes

The table uses a transparent estimate: 72B × bytes-per-weight (Q4 0.58, Q8 1.06), then compares against usable memory — full VRAM on discrete GPUs, ~70% on Apple unified memory, ~80% on CPU-only system RAM. A verdict needs the weights plus 2 GB of headroom for context and runtime buffers.

Longer context windows consume additional memory beyond the weights. If you run 32k+ token contexts, treat “Tight fit” as “no” and give “Runs well” setups extra headroom.