Can SmolLM3 3B run on RX 7900 XT 20GB?

YES — Runs Great

C54Usable

Estimated from fit model

SmolLM3 3B needs ~6.7 GB VRAM. RX 7900 XT 20GB has 20.0 GB. With Q4_K_M quantization, expect ~42 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) — 6.7 GB, 42.0 tok/s, Runs well

6.7 GB required20.0 GB available

34% VRAM used

Fit status

Runs well

Decode

42.0 tok/s

TTFT

4610 ms

Safe context

125K

Memory

6.7 GB / 20.0 GB

Memory breakdown

Weights1.8 GB

KV Cache2.0 GB

Runtime0.9 GB

Headroom2.0 GB

See how fast it feels

See how fast it feelsSmolLM3 3B on RX 7900 XT 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: 42.0 tok/s decode · 4.6s TTFT (warm) · 105 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	C	Runs well	42.0 tok/s	2514 ms	125K
Coding	C	Runs well	42.0 tok/s	4610 ms	125K
Agentic Coding	B	Runs well	42.0 tok/s	6705 ms	125K
Reasoning	C	Runs well	42.0 tok/s	5448 ms	125K
RAG	B	Runs well	42.0 tok/s	8381 ms	125K

Quantization options

How SmolLM3 3B (3B params) fits at each quantization level on RX 7900 XT 20GB (20.0 GB usable).

Quant	Bits	VRAM	Quality	Fit
Q2_K	2	1.2 GB	Low	C52
Q3_K_S	3	1.5 GB	Low	C52
NVFP4	4

Get started

Copy-paste commands to run SmolLM3 3B on your machine.

Run

lms load SmolLM3-3B && lms server start

Upgrade options

Hardware that runs SmolLM3 3B well

MacBook Pro M4 32GBBudget pick

32 GB Unified (+12)

This setup is broadly balanced for this model.42 tok/s decode

~$799 MSRP

Mac mini M4 32GBBest value

32 GB Unified (+12)

This setup is broadly balanced for this model.42 tok/s decode

~$1,099 MSRP

Frequently asked questions

Can RX 7900 XT 20GB run SmolLM3 3B?

Yes, RX 7900 XT 20GB can run SmolLM3 3B with a C grade (Runs well). Expected decode speed: 42.0 tok/s.

How much VRAM does SmolLM3 3B need?

SmolLM3 3B (3B parameters) requires approximately 6.7 GB of memory with Q4_K_M quantization.

What is the best quantization for SmolLM3 3B?

The recommended quantization for SmolLM3 3B is Q4_K_M, which balances quality and memory efficiency.

What speed will SmolLM3 3B run at on RX 7900 XT 20GB?

On RX 7900 XT 20GB, SmolLM3 3B achieves approximately 42.0 tokens per second decode speed with a time-to-first-token of 4610ms using Q4_K_M quantization.

Can RX 7900 XT 20GB run SmolLM3 3B for coding?

For coding workloads, SmolLM3 3B on RX 7900 XT 20GB receives a C grade with 42.0 tok/s and 125K context.

What context window can SmolLM3 3B use on RX 7900 XT 20GB?

On RX 7900 XT 20GB, SmolLM3 3B can safely use up to 125K 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 SmolLM3 3B

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