Can I run Phi-3 mini 3.8B on NVIDIA RTX 4070 12GB?
Yes: Phi-3 mini 3.8B runs on NVIDIA RTX 4070 12GB with Q8_0 at roughly 45 tokens/s. Estimated memory 7.5 GiB at 8,192 tokens of context.
Memory by quantisation (8,192-token context)
| Quantisation | Memory | Verdict | Est. speed |
|---|---|---|---|
| F16Unquantized reference | 10.9 GiB | Tight | ~30 tok/s |
| Q8_0Near-lossless | 7.5 GiB | Fits | ~45 tok/s |
| Q6_KVery close to F16 | 6.7 GiB | Fits | ~52 tok/s |
| Q5_K_MGreat quality/size | 6.3 GiB | Fits | ~55 tok/s |
| Q4_K_MBest default for most | 5.9 GiB | Fits | ~59 tok/s |
| IQ4_XSSmaller 4-bit (imatrix) | 5.6 GiB | Fits | ~62 tok/s |
| Q3_K_MNoticeable loss | 5.5 GiB | Fits | ~64 tok/s |
| Q2_KLast resort; big loss | 5.2 GiB | Fits | ~68 tok/s |
NVIDIA RTX 4070 12GB offers about 12 GiB of memory (92% usable for a model) at 504 GB/s. Speed is a bandwidth-bound estimate of single-stream generation at 65% efficiency; real results vary by runtime, drivers and settings, so measure on your machine.
How this is calculated
Weights ≈ parameters × bits per weight ÷ 8. KV cache ≈ 2 × 32 layers × 32 KV heads × 96 head dim × 2 bytes per token. Decode speed ≈ efficiency × memory bandwidth ÷ bytes read per token. Learn the maths in VRAM math and memory bandwidth, or try the VRAM calculator.
Phi-3 mini 3.8B on other hardware
Similar models on NVIDIA RTX 4070 12GB
Running slowly or out of memory? See CUDA out of memory and the quantisation lesson.