RTX 4070 12GB runs Phi-4 (14B) — but there's less headroom than you'd think
Sized at Q4_K_M with a 8K context: weights, KV cache and framework overhead, against what RTX 4070 12GB leaves free. Phi-4 (14B) at Q4_K_M needs 10.9 GB and you have 12 GB available, so it fits with 1.1 GB to spare. Expect 28.6–55 tok/s (estimated).
What to do
Phi-4 (14B) at Q4_K_M needs 10.9 GB and you have 12 GB available, so it fits with 1.1 GB to spare.
- VRAM required at Q4_K_M and 8K context: 10.9 GB
- VRAM available on your hardware: 12 GB
Your machine is not exactly this one. Run this for your exact setup — the form opens pre-filled with RTX 4070 12GB and Phi-4 (14B).
Questions people ask about this pairing
Can an RTX 4070 12GB run Phi-4 (14B)?
Yes. Phi-4 (14B) at Q4_K_M needs 10.9 GB and you have 12 GB available, so it fits with 1.1 GB to spare.
How fast will Phi-4 (14B) actually run?
Around 28.6–55 tok/s (estimated) on this setup at Q4_K_M. Decode speed on a local model is set by memory bandwidth rather than compute, so the figure moves with the card's bandwidth and the bytes read per token — not with its price.
Does a longer context change what Phi-4 (14B) needs here?
Yes, and it is the figure people forget. The 10.9 GB above already includes the KV cache at 8K; that cache grows roughly linearly with context, so doubling the window adds real gigabytes rather than a rounding error. If you plan to work with long documents on RTX 4070 12GB, size for the context you will actually use, not the default.
Related
- Phi-4 (14B) — full specs and VRAM by quantization
- NVIDIA GeForce RTX 4070 — specifications and what else it runs
- Can I run Phi-4 (14B) on a NVIDIA GeForce RTX 4070?
- VRAM calculator for Phi-4 (14B)
- RTX 4070 12GB → Qwen 3 32B: change a setting
- MacBook Air M2, 8GB → Phi-4 (14B): a different machine
- RTX 5070 12GB → Phi-4 (14B): keep what you have
Data behind this page last checked 2026-07-12.