Can Phi-4-reasoning-plus 14B run on RX 6900 XT 16GB?

YES — Tight Fit

S90Excellent

Estimated from fit model

Phi-4-reasoning-plus 14B needs ~14.5 GB VRAM. RX 6900 XT 16GB has 16.0 GB. With Q4_K_M quantization, expect ~35 tok/s.

Runtime: llama.cppCapacity: TightBandwidth: MediumStack: 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) — 14.5 GB, 35.0 tok/s, Tight fit

14.5 GB required16.0 GB available

91% VRAM used

Fit status

Tight fit

Decode

35.0 tok/s

TTFT

5533 ms

Safe context

24K

Memory

14.5 GB / 16.0 GB

Memory breakdown

Weights9.0 GB

KV Cache3.1 GB

Runtime0.9 GB

Headroom1.6 GB

See how fast it feels

See how fast it feelsPhi-4-reasoning-plus 14B on RX 6900 XT 16GB
1st promptCold start — includes initialization
>Solve: If a train travels at 60 mph for 2.5 hours, how far does it go?
Let me work through this step by step.

Given information:
  - Speed = 60 mph (miles per hour)
  - Time  = 2.5 hours

Formula: Distance = Speed x Time

Calculation:
  Distance = 60 mph x 2.5 h
           = 150 miles

The train travels 150 miles.

Double-check: at 60 mph the train covers 60 miles each hour. In half an hour it covers 30 miles. So in 2.5 hours: 60 + 60 + 30 = 150 miles. Confirmed.
2nd promptWarm — model ready, no init overhead
>What if the train stops for 20 minutes halfway?
The stop doesn't change the total distance covered while moving, but it affects total trip time.

Breakdown:
  - First half: 1.25 hours at 60 mph = 75 miles
  - Stop: 20 minutes (no distance)
  - Second half: 1.25 hours at 60 mph = 75 miles

Total distance: 150 miles (same)
Total time: 2.5 h + 0.33 h = 2.83 hours
Average speed: 150 / 2.83 = 53 mph

The distance stays the same but average speed drops to 53 mph because of the stop.
Estimated: 35.0 tok/s decode · 5.5s TTFT (warm) · 88 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	S	Runs well	35.0 tok/s	3018 ms	24K
Coding	S	Tight fit	35.0 tok/s	5533 ms	24K
Agentic Coding	A	Very compromised (needs ~0.8 GB host RAM)	21.5 tok/s	13070 ms	24K
Reasoning	S	Tight fit	35.0 tok/s	6540 ms	24K
RAG	A	Very compromised (needs ~0.8 GB host RAM)	21.5 tok/s	16337 ms

Quantization options

How Phi-4-reasoning-plus 14B (14.699999809265137B params) fits at each quantization level on RX 6900 XT 16GB (16.0 GB usable).

Quant	Bits	VRAM	Quality	Fit
Q2_K	2	5.7 GB	Low	S89
Q3_K_S	3	7.2 GB	Low	S91
NVFP4	4

Get started

Copy-paste commands to run Phi-4-reasoning-plus 14B on your machine.

Run

ollama run phi4-reasoning

Frequently asked questions

Can RX 6900 XT 16GB run Phi-4-reasoning-plus 14B?

Yes, RX 6900 XT 16GB can run Phi-4-reasoning-plus 14B with a S grade (Tight fit). Expected decode speed: 35.0 tok/s.

How much VRAM does Phi-4-reasoning-plus 14B need?

Phi-4-reasoning-plus 14B (14.699999809265137B parameters) requires approximately 14.5 GB of memory with Q4_K_M quantization.

What is the best quantization for Phi-4-reasoning-plus 14B?

The recommended quantization for Phi-4-reasoning-plus 14B is Q4_K_M, which balances quality and memory efficiency.

What speed will Phi-4-reasoning-plus 14B run at on RX 6900 XT 16GB?

On RX 6900 XT 16GB, Phi-4-reasoning-plus 14B achieves approximately 35.0 tokens per second decode speed with a time-to-first-token of 5533ms using Q4_K_M quantization.

Can RX 6900 XT 16GB run Phi-4-reasoning-plus 14B for coding?

For coding workloads, Phi-4-reasoning-plus 14B on RX 6900 XT 16GB receives a S grade with 35.0 tok/s and 24K context.

What context window can Phi-4-reasoning-plus 14B use on RX 6900 XT 16GB?

On RX 6900 XT 16GB, Phi-4-reasoning-plus 14B can safely use up to 24K tokens of context. The model's official context limit is 33K, but available memory constrains the safe maximum.

See all results for RX 6900 XT 16GB See all hardware for Phi-4-reasoning-plus 14B

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