Will It Run AI

Can Phi-4-reasoning-plus 14B run on Mac Studio M3 Ultra 256GB?

YES — Runs Great

S85Excellent
Estimated from fit model

Phi-4-reasoning-plus 14B needs ~40.6 GB VRAM. Mac Studio M3 Ultra 256GB has 184.3 GB. With Q4_K_M quantization, expect ~67 tok/s.

Runtime: llama.cppCapacity: RoomyBandwidth: HighStack: StandardBottleneck: Balanced
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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) — 40.6 GB, 66.8 tok/s, Runs well
40.6 GB required184.3 GB available
22% VRAM used

Fit status

Runs well

Decode

66.8 tok/s

TTFT

2900 ms

Safe context

33K

Memory

40.6 GB / 184.3 GB

Memory breakdown

Weights9.0 GB
KV Cache3.1 GB
Runtime0.9 GB
Headroom27.6 GB

See how fast it feels

See how fast it feelsPhi-4-reasoning-plus 14B on Mac Studio M3 Ultra 256GB
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: 66.8 tok/s decode · 2.9s TTFT (warm) · 167 tok/s prefill

What limits this setup

This setup is broadly balanced for this model.

Shared-memory contention still exists

The OS, browser, and inference runtime all compete for the same physical memory pool, so real-world headroom is less forgiving than raw capacity suggests.

Best improvement path

Performance by workload

WorkloadGradeFitDecodeTTFTContext
ChatSRuns well66.8 tok/s1582 ms33K
CodingSRuns well66.8 tok/s2900 ms33K
Agentic CodingSRuns well66.8 tok/s4218 ms33K
ReasoningSRuns well66.8 tok/s3427 ms33K
RAGSRuns well66.8 tok/s5272 ms33K

Quantization options

How Phi-4-reasoning-plus 14B (14.699999809265137B params) fits at each quantization level on Mac Studio M3 Ultra 256GB (184.3 GB usable).

QuantBitsVRAMQualityFit
Q2_K
2
5.7 GB
LowA77
Q3_K_S
3
7.2 GB
LowA77
NVFP4
4
8.2 GB
MediumA77
Q4_K_M
4
9.0 GB
MediumA77
Q5_K_M
5
10.6 GB
HighA77
Q6_K
6
12.1 GB
HighA77
Q8_0
8
15.7 GB
Very HighA77
F16Best for your GPU
16
30.1 GB
MaximumA78

Get started

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

Run

ollama run phi4-reasoning

Your hardware

More models your Mac Studio M3 Ultra 256GB can run

ModelParamsGradeDecodeCapabilities
MistralDevstral 2 123B Instruct123BS8.1 tok/s
AlibabaQwen3-Coder 30B A3B Instruct30.5BS84.2 tok/s
AlibabaQwen 3.5 27B27BS36.5 tok/s
AlibabaQwen 3.6 27B27BS27.8 tok/s
AlibabaQwen 3.5 122B A10B122BS34.7 tok/s

Frequently asked questions

Can Mac Studio M3 Ultra 256GB run Phi-4-reasoning-plus 14B?

Yes, Mac Studio M3 Ultra 256GB can run Phi-4-reasoning-plus 14B with a S grade (Runs well). Expected decode speed: 66.8 tok/s.

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

Phi-4-reasoning-plus 14B (14.699999809265137B parameters) requires approximately 40.6 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 Mac Studio M3 Ultra 256GB?

On Mac Studio M3 Ultra 256GB, Phi-4-reasoning-plus 14B achieves approximately 66.8 tokens per second decode speed with a time-to-first-token of 2900ms using Q4_K_M quantization.

Can Mac Studio M3 Ultra 256GB run Phi-4-reasoning-plus 14B for coding?

For coding workloads, Phi-4-reasoning-plus 14B on Mac Studio M3 Ultra 256GB receives a S grade with 66.8 tok/s and 33K context.

What context window can Phi-4-reasoning-plus 14B use on Mac Studio M3 Ultra 256GB?

On Mac Studio M3 Ultra 256GB, Phi-4-reasoning-plus 14B can safely use up to 33K tokens of context. The model's official context limit is 33K, but available memory constrains the safe maximum.

Is unified memory on Mac Studio M3 Ultra 256GB as fast as VRAM for Phi-4-reasoning-plus 14B?

Not always. Mac Studio M3 Ultra 256GB can often fit larger models thanks to unified memory, but a discrete GPU with dedicated high-bandwidth VRAM may still decode faster once the model fits. For this combination, the important distinction is capacity versus sustained throughput.

See all results for Mac Studio M3 Ultra 256GBSee all hardware for Phi-4-reasoning-plus 14B
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