Compatibility check
Can you run Phi-4 on the RTX 3080?
Yes, with quantization. Phi-4 does not fit the RTX 3080 (10 GB) in FP16, but it runs at INT4 (4-bit) using about 9.2 GB (92% of VRAM). Use a GPTQ, AWQ, or GGUF build to get there, and keep prompts moderate to leave room for the KV cache.
Memory breakdown
Weights plus a 0.8 GB KV cache at 4,096tokens, against the card's 10 GB. Verdicts leave ~10% headroom for activations and fragmentation.
| Precision | Weights | KV cache | Total | % of 10 GB | Fit |
|---|---|---|---|---|---|
| FP16 / BF16full quality | 33.7 GB | 0.8 GB | 34.5 GB | 345% | No |
| INT8 (8-bit)near-full quality | 16.9 GB | 0.8 GB | 17.7 GB | 177% | No |
| INT4 (4-bit)GPTQ / AWQ / GGUF Q4 | 8.4 GB | 0.8 GB | 9.2 GB | 92% | Tight |
Planning estimates, not a substitute for profiling. Real usage varies with the inference runtime, batch size, and how much context you actually use — the KV cache grows linearly with prompt length.
GPUs that run Phi-4
Cards where this model fits (at its best precision):
Models that fit the RTX 3080
Other popular models that run on this card:
Go deeper
Frequently asked questions
Can the RTX 3080 run Phi-4?
Not in FP16, but yes at INT4 (4-bit), where it uses about 9.2 GB versus the card's 10 GB.
How much VRAM does Phi-4 need?
Approximately 33.7 GB in FP16, 16.9 GB in INT8, and 8.4 GB in 4-bit for the weights, plus a KV cache of about 0.8 GB at 4,096 tokens.
Does quantization let Phi-4 fit on the RTX 3080?
Yes. Dropping to INT4 (4-bit) brings total usage to about 9.2 GB, which fits the 10 GB card with headroom for the KV cache.
What happens to memory with longer context?
The KV cache grows linearly with prompt length. At 4,096 tokens it is about 0.8 GB here; doubling the context roughly doubles that term, so long-context use can push a tight fit over the edge.