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

Your machine already runs this

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.

What we checked
  • 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

Data behind this page last checked 2026-07-12.