Can Phi 3 Medium 14B run on RTX 4000 Ada 20GB?

YES — Runs Great

B65Good

Estimated from fit model

Phi 3 Medium 14B needs ~14.8 GB VRAM. RTX 4000 Ada 20GB has 20.0 GB. With Q4_K_M quantization, expect ~35 tok/s.

Runtime: OllamaCapacity: RoomyBandwidth: LowStack: BasicBottleneck: 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) — 14.8 GB, 35.3 tok/s, Runs well

14.8 GB required20.0 GB available

74% VRAM used

Fit status

Runs well

Decode

35.3 tok/s

TTFT

5477 ms

Safe context

43K

Memory

14.8 GB / 20.0 GB

Memory breakdown

Weights8.5 GB

KV Cache3.1 GB

Runtime1.2 GB

Headroom2.0 GB

See how fast it feels

See how fast it feelsPhi 3 Medium 14B on RTX 4000 Ada 20GB
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: 35.3 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	B	Runs well	35.3 tok/s	2988 ms	43K
Coding	B	Runs well	35.3 tok/s	5477 ms	43K
Agentic Coding	B	Tight fit	35.3 tok/s	7967 ms	43K
Reasoning	B	Runs well	35.3 tok/s	6473 ms	43K
RAG	B	Tight fit	35.3 tok/s	9959 ms	43K

Quantization options

How Phi 3 Medium 14B (14B params) fits at each quantization level on RTX 4000 Ada 20GB (20.0 GB usable).

Quant	Bits	VRAM	Quality	Fit
Q2_K	2	5.5 GB	Low	B58
Q3_K_S	3	6.9 GB	Low	B59
NVFP4	4

Get started

Copy-paste commands to run Phi 3 Medium 14B on your machine.

Run

ollama run phi3:medium

Upgrade options

Hardware that runs Phi 3 Medium 14B well

RTX 3090 24GBBudget pick

24 GB VRAM (+4)936 GB/s (+576)

Raises estimated decode speed by about 134%.82.5 tok/s decode

Raises estimated decode speed by about 134%.

~$1,499 MSRP

RTX 4090 24GBBest value

24 GB VRAM (+4)1008 GB/s (+648)

Raises estimated decode speed by about 173%.96.4 tok/s decode

Raises estimated decode speed by about 173%.

~$1,599 MSRP

RTX PRO 4000 Blackwell 24GBNVIDIA upgrade

24 GB VRAM (+4)672 GB/s (+312)

Raises estimated decode speed by about 101%.71.1 tok/s decode

Raises estimated decode speed by about 101%.

~$1,599 MSRP

Frequently asked questions

Can RTX 4000 Ada 20GB run Phi 3 Medium 14B?

Yes, RTX 4000 Ada 20GB can run Phi 3 Medium 14B with a B grade (Runs well). Expected decode speed: 35.3 tok/s.

How much VRAM does Phi 3 Medium 14B need?

Phi 3 Medium 14B (14B parameters) requires approximately 14.8 GB of memory with Q4_K_M quantization.

What is the best quantization for Phi 3 Medium 14B?

The recommended quantization for Phi 3 Medium 14B is Q4_K_M, which balances quality and memory efficiency.

What speed will Phi 3 Medium 14B run at on RTX 4000 Ada 20GB?

On RTX 4000 Ada 20GB, Phi 3 Medium 14B achieves approximately 35.3 tokens per second decode speed with a time-to-first-token of 5477ms using Q4_K_M quantization.

Can RTX 4000 Ada 20GB run Phi 3 Medium 14B for coding?

For coding workloads, Phi 3 Medium 14B on RTX 4000 Ada 20GB receives a B grade with 35.3 tok/s and 43K context.

What context window can Phi 3 Medium 14B use on RTX 4000 Ada 20GB?

On RTX 4000 Ada 20GB, Phi 3 Medium 14B can safely use up to 43K tokens of context. The model's official context limit is 128K, but available memory constrains the safe maximum.

See all results for RTX 4000 Ada 20GB See all hardware for Phi 3 Medium 14B

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