Can Granite 3.1 8B run on Mac Studio M2 Ultra 64GB?

Q: Is unified memory on Mac Studio M2 Ultra 64GB as fast as VRAM for Granite 3.1 8B?

Not always. Mac Studio M2 Ultra 64GB 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.

YES — Runs Great

C53Usable

Estimated from fit model

Granite 3.1 8B needs ~14.6 GB VRAM. Mac Studio M2 Ultra 64GB has 46.1 GB. With Q4_K_M quantization, expect ~109 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) — 14.6 GB, 112.0 tok/s, Runs well

14.6 GB required46.1 GB available

32% VRAM used

Fit status

Runs well

Decode

112.0 tok/s

TTFT

1729 ms

Safe context

128K

Memory

14.6 GB / 46.1 GB

Memory breakdown

Weights4.9 GB

KV Cache2.0 GB

Runtime0.9 GB

Headroom6.9 GB

See how fast it feels

See how fast it feelsGranite 3.1 8B on Mac Studio M2 Ultra 64GB
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: 112.0 tok/s decode · 1.7s TTFT (warm) · 280 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

Workload	Grade	Fit	Decode	TTFT	Context
Chat	C	Runs well	112.0 tok/s	943 ms	128K
Coding	C	Runs well	109.3 tok/s	1771 ms	128K
Agentic Coding	C	Runs well	112.0 tok/s	2514 ms	128K
Reasoning	C	Runs well	112.0 tok/s	2043 ms	128K
RAG	C	Runs well	112.0 tok/s	3143 ms	128K

Quantization options

How Granite 3.1 8B (8B params) fits at each quantization level on Mac Studio M2 Ultra 64GB (46.1 GB usable).

Quant	Bits	VRAM	Quality	Fit
Q2_K	2	3.1 GB	Low	C46
Q3_K_S	3	3.9 GB	Low	C46
NVFP4	4

Get started

Copy-paste commands to run Granite 3.1 8B on your machine.

Run

ollama run granite3.1-dense

Frequently asked questions

Can Mac Studio M2 Ultra 64GB run Granite 3.1 8B?

Yes, Mac Studio M2 Ultra 64GB can run Granite 3.1 8B with a C grade (Runs well). Expected decode speed: 109.3 tok/s.

How much VRAM does Granite 3.1 8B need?

Granite 3.1 8B (8B parameters) requires approximately 14.6 GB of memory with Q4_K_M quantization.

What is the best quantization for Granite 3.1 8B?

The recommended quantization for Granite 3.1 8B is Q4_K_M, which balances quality and memory efficiency.

What speed will Granite 3.1 8B run at on Mac Studio M2 Ultra 64GB?

On Mac Studio M2 Ultra 64GB, Granite 3.1 8B achieves approximately 109.3 tokens per second decode speed with a time-to-first-token of 1771ms using Q4_K_M quantization.

Can Mac Studio M2 Ultra 64GB run Granite 3.1 8B for coding?

For coding workloads, Granite 3.1 8B on Mac Studio M2 Ultra 64GB receives a C grade with 109.3 tok/s and 128K context.

What context window can Granite 3.1 8B use on Mac Studio M2 Ultra 64GB?

On Mac Studio M2 Ultra 64GB, Granite 3.1 8B can safely use up to 128K tokens of context. The model's official context limit is 128K, but available memory constrains the safe maximum.

Is unified memory on Mac Studio M2 Ultra 64GB as fast as VRAM for Granite 3.1 8B?

See all results for Mac Studio M2 Ultra 64GB See all hardware for Granite 3.1 8B

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