LLM VRAM Checker

Running Phi-4 14B locally

Microsoft · 14B parameters · released 2024-12

Microsoft’s small-model line focused on reasoning quality per parameter. Efficient at 14B and friendly to 12 GB cards.

Q4 — 4-bit quantized

≈ 8.1 GB

weights only, plus 2 GB context headroom rule

Q8 — 8-bit quantized

≈ 14.8 GB

weights only, plus 2 GB context headroom rule

Verdicts by hardware

HardwareUsableQ4 (8.1 GB)Q8 (14.8 GB)
RTX 4090 (24 GB)24 GBRuns wellRuns well
RTX 3090 (24 GB)24 GBRuns wellRuns well
RTX 4070 Ti SUPER (16 GB)16 GBRuns wellTight fit
RTX 4060 Ti (16 GB)16 GBRuns wellTight fit
RTX 3060 (12 GB)12 GBRuns wellToo 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 GBRuns wellRuns well
Mac Studio M2 Max (64 GB unified)44.8 GBRuns wellRuns well
CPU only (32 GB system RAM)25.6 GBRuns wellRuns well
CPU only (16 GB system RAM)12.8 GBRuns wellToo big

Notes

The table uses a transparent estimate: 14B × 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.