Can StarCoder2 15B run on Mac Studio M3 Ultra 256GB?

YES — Runs Great

C45Usable
Estimated from fit model

StarCoder2 15B needs ~39.5 GB VRAM. Mac Studio M3 Ultra 256GB has 184.3 GB. With Q4_K_M quantization, expect ~61 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) 39.5 GB, 60.9 tok/s, Runs well
39.5 GB required184.3 GB available
21% VRAM used

Fit status

Runs well

Decode

60.9 tok/s

TTFT

3181 ms

Safe context

1.3M

Memory

39.5 GB / 184.3 GB

Memory breakdown

Weights9.2 GB
KV Cache1.8 GB
Runtime0.9 GB
Headroom27.6 GB

See how fast it feels

See how fast it feelsStarCoder2 15B on Mac Studio M3 Ultra 256GB
1st promptCold start — includes initialization
>Write a Python function to sort a list
Here's a Python function that sorts a list using quicksort: def quicksort(arr): if len(arr) <= 1: return arr pivot = arr[len(arr) // 2] left = [x for x in arr if x < pivot] middle = [x for x in arr if x == pivot] right = [x for x in arr if x > pivot] return quicksort(left) + middle + quicksort(right) # Example usage numbers = [3, 6, 8, 10, 1, 2, 1] print(quicksort(numbers)) # [1, 1, 2, 3, 6, 8, 10] The algorithm picks a pivot, partitions the list into smaller, equal, and larger elements, then recursively sorts each partition and concatenates the results.
2nd promptWarm — model ready, no init overhead
>Now add type hints and a docstring
def quicksort(arr: list[int]) -> list[int]: """Sort a list using the quicksort algorithm. Args: arr: List of integers to sort. Returns: A new sorted list. """ if len(arr) <= 1: return arr pivot = arr[len(arr) // 2] left = [x for x in arr if x < pivot] middle = [x for x in arr if x == pivot] right = [x for x in arr if x > pivot] return quicksort(left) + middle + quicksort(right) Added type hints for the input and return type, plus a Google-style docstring.
Estimated: 60.9 tok/s decode · 3.2s TTFT (warm) · 152 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
ChatCRuns well60.9 tok/s1735 ms1.3M
CodingCRuns well60.9 tok/s3181 ms1.3M
Agentic CodingCRuns well60.9 tok/s4627 ms1.3M
ReasoningCRuns well60.9 tok/s3759 ms1.3M
RAGCRuns well60.9 tok/s5783 ms1.3M

Quantization options

How StarCoder2 15B (15B params) fits at each quantization level on Mac Studio M3 Ultra 256GB (184.3 GB usable).

QuantBitsVRAMQualityFit
Q2_K
2
5.9 GB
LowD37
Q3_K_S
3
7.4 GB
LowD37
NVFP4
4
8.4 GB
MediumD37
Q4_K_M
4
9.2 GB
MediumD37
Q5_K_M
5
10.8 GB
HighD37
Q6_K
6
12.3 GB
HighD37
Q8_0
8
16.1 GB
Very HighD37
F16Best for your GPU
16
30.7 GB
MaximumD39

Get started

Copy-paste commands to run StarCoder2 15B on your machine.

Run

lms load hf-second-state--starcoder2-15b-gguf && lms server start

Upgrade-Optionen

Hardware, die StarCoder2 15B gut ausführt

Frequently asked questions

Can Mac Studio M3 Ultra 256GB run StarCoder2 15B?

Yes, Mac Studio M3 Ultra 256GB can run StarCoder2 15B with a C grade (Runs well). Expected decode speed: 60.9 tok/s.

How much VRAM does StarCoder2 15B need?

StarCoder2 15B (15B parameters) requires approximately 39.5 GB of memory with Q4_K_M quantization.

What is the best quantization for StarCoder2 15B?

The recommended quantization for StarCoder2 15B is Q4_K_M, which balances quality and memory efficiency.

What speed will StarCoder2 15B run at on Mac Studio M3 Ultra 256GB?

On Mac Studio M3 Ultra 256GB, StarCoder2 15B achieves approximately 60.9 tokens per second decode speed with a time-to-first-token of 3181ms using Q4_K_M quantization.

Can Mac Studio M3 Ultra 256GB run StarCoder2 15B for coding?

For coding workloads, StarCoder2 15B on Mac Studio M3 Ultra 256GB receives a C grade with 60.9 tok/s and 1.3M context.

What context window can StarCoder2 15B use on Mac Studio M3 Ultra 256GB?

On Mac Studio M3 Ultra 256GB, StarCoder2 15B can safely use up to 1.3M tokens of context. The model's official context limit is —, but available memory constrains the safe maximum.

Is unified memory on Mac Studio M3 Ultra 256GB as fast as VRAM for StarCoder2 15B?

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 StarCoder2 15B
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