Can Phi 3 Mini 3.8B run on RX 7900 XT 20GB?

YES — Runs Great

B69Good

Estimated from fit model

Phi 3 Mini 3.8B needs ~11.1 GB VRAM. RX 7900 XT 20GB has 20.0 GB. With Q4_K_M quantization, expect ~53 tok/s.

Runtime: llama.cppCapacity: RoomyBandwidth: HighStack: StandardBottleneck: Balanced

Operating mode

Choose the run profile you care about

Interactive favors responsiveness, while light API and scale-out lean harder on serving readiness. The fit stays the same, but the recommendation lens changes.

Current mode

Balanced

Balanced for general local use. Keeps the ranking neutral across personal and serving workflows.

Capabilities:

Select quantization to explore

Q4_K_M (Medium quality) — 11.1 GB, 53.2 tok/s, Runs well

11.1 GB required20.0 GB available

55% VRAM used

Fit status

Runs well

Decode

53.2 tok/s

TTFT

3639 ms

Safe context

40K

Memory

11.1 GB / 20.0 GB

Memory breakdown

Weights2.3 GB

KV Cache5.9 GB

Runtime0.9 GB

Headroom2.0 GB

See how fast it feels

See how fast it feelsPhi 3 Mini 3.8B on RX 7900 XT 20GB
1st promptCold start — includes initialization
>What is local AI inference?
Local AI inference means running an AI language model directly on your own hardware — your laptop, desktop, or server — instead of sending requests to a remote cloud API.

When you run inference locally the model weights are loaded into your GPU or unified memory. Each token you generate requires reading those weights from memory, so memory bandwidth is the main bottleneck for decode speed.

Key benefits of running locally:
  - Full privacy: your prompts never leave your machine
  - No per-token cost or rate limits
  - Works offline once the model is downloaded
  - Latency depends only on your hardware
2nd promptWarm — model ready, no init overhead
>How much VRAM do I need?
It depends on the model size and quantization level. A rough rule of thumb:

  Model size     Q4 (4-bit)    Q8 (8-bit)    FP16
  7B params      ~4.3 GB       ~7.5 GB       ~14 GB
  13B params     ~7.9 GB       ~13.9 GB      ~26 GB
  70B params     ~42.7 GB      ~74.9 GB      ~140 GB

Most people use 4-bit quantization (Q4_K_M) which gives 90-95% of full quality at a fraction of the memory. A 24 GB GPU can comfortably run most 7B-13B models.
Estimated: 53.2 tok/s decode · 3.6s TTFT (warm) · 133 tok/s prefill

What limits this setup

This setup is broadly balanced for this model.

No major red flags

This recommendation has enough memory headroom and acceptable estimated speed for the selected workload.

Best improvement path

Performance by workload

Workload	Grade	Fit	Decode	TTFT	Context
Chat	B	Runs well	53.2 tok/s	1985 ms	40K
Coding	B	Runs well	53.2 tok/s	3639 ms	40K
Agentic Coding	B	Tight fit	53.2 tok/s	5293 ms	40K
Reasoning	B	Runs well	53.2 tok/s	4301 ms	40K
RAG	B	Tight fit	53.2 tok/s	6617 ms	40K

Quantization options

How Phi 3 Mini 3.8B (3.799999952316284B params) fits at each quantization level on RX 7900 XT 20GB (20.0 GB usable).

Quant	Bits	VRAM	Quality	Fit
Q2_K	2	1.5 GB	Low	B62
Q3_K_S	3	1.9 GB	Low	B62
NVFP4	4	2.1 GB	Medium	B62
Q4_K_M	4	2.3 GB	Medium	B62
Q5_K_M	5	2.7 GB	High	B62
Q6_K	6	3.1 GB	High	B63
Q8_0	8	4.1 GB	Very High	B63
F16Best for your GPU	16	7.8 GB	Maximum	B66

Get started

Copy-paste commands to run Phi 3 Mini 3.8B on your machine.

Run

ollama run phi3:mini

Frequently asked questions

Can RX 7900 XT 20GB run Phi 3 Mini 3.8B?

Yes, RX 7900 XT 20GB can run Phi 3 Mini 3.8B with a B grade (Runs well). Expected decode speed: 53.2 tok/s.

How much VRAM does Phi 3 Mini 3.8B need?

Phi 3 Mini 3.8B (3.799999952316284B parameters) requires approximately 11.1 GB of memory with Q4_K_M quantization.

What is the best quantization for Phi 3 Mini 3.8B?

The recommended quantization for Phi 3 Mini 3.8B is Q4_K_M, which balances quality and memory efficiency.

What speed will Phi 3 Mini 3.8B run at on RX 7900 XT 20GB?

On RX 7900 XT 20GB, Phi 3 Mini 3.8B achieves approximately 53.2 tokens per second decode speed with a time-to-first-token of 3639ms using Q4_K_M quantization.

Can RX 7900 XT 20GB run Phi 3 Mini 3.8B for coding?

For coding workloads, Phi 3 Mini 3.8B on RX 7900 XT 20GB receives a B grade with 53.2 tok/s and 40K context.

What context window can Phi 3 Mini 3.8B use on RX 7900 XT 20GB?

On RX 7900 XT 20GB, Phi 3 Mini 3.8B can safely use up to 40K tokens of context. The model's official context limit is 128K, but available memory constrains the safe maximum.

See all results for RX 7900 XT 20GB See all hardware for Phi 3 Mini 3.8B

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